A: Like cars, knife sharpeners run the gamut from basic to luxury and like cars the price can vary from extremely affordable to more than some people might want to spend. You can get a high quality sharpener that will put your knives through a 2 or 3-stage process which will result in an incredibly sharp edge for less than $20. Or you can buy a mechanical sharpener that will produce a virtually flawless edge for $200+.

The humble sharpener tends to elicit more divergent opinions than just about any other type of kitchen tech. Everyone, it turns out, has their own take on which type of sharpener works best and why and most serious chefs aren’t shy about voicing their opinion. As you can imagine then there are a number of things most chefs – both professional and amateur – look for in a sharpener in order to ensure they get the one that’s right for them. These considerations include:
To use Al's method, take a black felt pen and shade in the bevel of the knife. Then take two strokes on the stone and examine the edge. If you have maintained the proper angle then all the black will be gone. If you see black on the top of the edge it means you are holding the back of the knife too far from the stone. If there is black on the bottom of the edge but the top is clean then you are laying the knife too flat on the stone and you need to raise it a bit. Repaint the edge and try it again. Once you discover what the right angle looks like then just maintain that.
I would say they are worth the money. Go for it. I took a blunted Pampered Chef kitchen knife from completely dull to razor sharp in about an hour (of bumbling and repairing mistakes LOL) heavy grinding. If you have a severely damaged blade, grab one of those cheesey two sided stones from Harbor Freight to do your heavy grinding. From there these stones will work very well.
Selecting the proper coarseness for your sharpening stone is an important first step in sharpening your knife. Not every knife needs to start at the coarsest stone you have, on the other hand a very dull knife can not be sharpened on only your finest stone. Starting with the proper coarseness will ensure that you achieve the edge you need quickly. If your knife is very dull or has a nicked blade, start with your coarsest stone. The coarse stone removes material quickly so a poor edge can be refined quickly. However, the coarse stone must be followed up with your finer stone to refine the edge. If your knife is only slightly dull and just needs a quick touch up, starting at a medium or fine stone can save you time. Starting on a fine stone requires fewer steps but must only be used on an edge requiring little work.

A: We’re all told that a sharp knife is safer than a dull knife yet most everyone knows that merely touching a sharp knife can often result in a painful cut while we can wrap our hand around a dull blade with little worry. So why would anyone in their right mind claim that a sharp one is safer than a dull one? To a certain extent it’s a matter of semantics for sure, because there is no denying you have to be extremely careful around really sharp knives. But at the same time there is a very good reason to consider a dull knife to be more of a safety hazard than a sharp knife.

However, due to limited natural deposits and extensive quarrying over the centuries, true, high quality, Japanese water stones are now few and far between and are very expensive. Thus, various companies are now producing synthetic Japanese Water Stones which generally have a more consistent composition and grit size than natural stones as well as often begin somewhat harder and thus, lasting a bit longer; not to mention being cheaper to purchase.
The Whetstone 2-Sided Sharpening Stone is made from professional grade corundum and will sharpen everything from a razor blade to a cleaver and even a machete, should you happen to have a machete lying about that needs sharpening. This is the simplest type of sharpener it’s true but the company have obviously put a great deal of thought into the product.
Don't know. Not sure that I really care, as these stones definitely did the job that was asked of them, and did it with ease, even for a beginner whetstone user. I'll probably stick with them, at least until I get a lot more experience. Though, I do see a 10,000 or higher grit stone in my immediate future - more to play around with, than a feeling of genuine need.
A: Another issue that comes up with electric knife sharpeners is how to clean them. Or if, in fact, they actually need cleaning at all. The answer to the second question is that yes, they do need to be cleaned occasionally. And by occasionally we mean once a year or so if you use them with any frequency. Obviously if you’ve only used the sharpener a few times then there’s no compelling reason to clean it, other than just wanting to keep things tidy (and there’s nothing wrong with that). So, having established that sharpeners do need to be cleaned occasionally you need to know how to do so in a safe and effective manner. It’s not complicated.
Over the course of two days I re-sharpened nearly a dozen old blades, including removing the secondary bevel on an old stainless Ontario saber-grind Navy diver's knife, convexing the edge on flat ground 1095 Schrade 55 that also came with a secondary bevel, and fixing a broken tip on an old Kershaw folder. These stones made quick work of the Schrade and Kershaw. Both had completely new edge geometry within 30 minutes apiece. The Kershaw looked like-new, as if the tip had never broken. And the Schrade cut much better than it's secondary bevel would previously allow, regardless of how sharp I got it with a ceramic rod and strops. The Ontario took a little more work, as it had been abused a little the last time I'd held it, over 25 years ago and was as dull as a case knife - one of the reasons I decided to go ahead and do a full saber grind - well, a slightly convexed saber, I suppose would be more accurate. But within under an hour of using the two stones and a couple leather strops (one with black compound, another with green), the Ontario was shaving sharp again too.
2. Although I’ve been sharpening knives for a while, I never could get a knife sharp using the freehand method, I’ve had to rely on various jigs to set & maintain a constant angle to the bevel. To begin with, the Lanksy knife sharpener kit was my main tool, but then I found a South African jig made by Warthog Knife Sharpeners. I still have their first model, which, if memory serves me, came out in the late 1990’s. This has since been upgraded & is supplied with a diamond stone, which is worthless unless it’s going to be used for ceramic knives. However-the Warthog & the Warthog Multi-Blade’s modus operandi has the knife moving ABOVE the stone, unlike the Lanksy / Edge Pro / Edge Pro Chinese copies & variants. ( No oil / water dripping off the stone from above the knife). Also, the Warthogs use any bench-size whetstone available to its owner, a very big plus if you want to use your grand-dad’s old Arkansas stone.No tie in having to buy the manufacturer’s specialised stones which work only with one type of sharpening jig.
Clamp-style sharpening tools use a clamp with several holes with predefined angles. The stone is mounted on a rod and is pulled through these holes, so that the angle remains consistent. Another system is the crock stick setup, where two sticks are put into a plastic or wooden base to form a V shape. When the knife is pulled up the V, the angle is held so long as the blade is held perpendicular to the base. Several cutlery manufacturers now offer electric knife sharpeners with multiple stages with at least one grinding stage. These electric sharpeners are typically used in the kitchen but have the ability to sharpen blades such as pocket or tactical knives. The main benefit of using an electric sharpener is speed with many models that can complete the sharpening process in one to two minutes. The disadvantage is that the sharpening angle is fixed so some specialized knives, like a Japanese style Santoku, may need additional attention to sharpen to the ideal angle.
I know that it is very helpful to watch a video of this process and the best videos of knife sharpening I have seen are out there for you. If you only watch one person sharpen a knife, watch Jon Broida from Japanese Knife Imports. Extremely professional videos and easy to understand. I have a couple of videos as well on my website but I really like what Jon has done for the sharpening community.
Once sufficiently wet, it's time to position the stone on something solid, so it doesn't move about during sharpening. Many come with holders, but you can just place it on a slightly damp tea towel on the table. The stone should be roughly perpendicular to your body, though Warner told me it is sometimes easier to angle it ever so slightly to the right (if you're right handed). 
The sharpener has come a long way in the past couple of thousand years and yet it hasn’t. That is, while there have been incredible advances in the development of mechanical knife sharpeners the classic and very ancient sharpening stone is still with us and very much in use as you read this. The best knife sharpener for you will be one that meets the needs of your cuisine and your temperament but which, first and foremost, reliably produces the sharp knives (look after your knife!) you need with the least hassle.
Therefore, the first step to choosing a whetstone is to determine your intended purpose and then choose your whetstone accordingly. For instance, when sharpening tools that do not require a fine edge, you should choose a relatively soft, coarse, stone such as a Norton Crystolon water stone. However, for sharpening tools that do require a fine edge, a somewhat harder Norton India oil stone would be a good choice. But, for sharpening hunting knives where an exceptionally fine edge is required, a Novaculite or Coticule oil stone would be the best but, most expensive, choice. So, the process of choosing the correct whetstone for any given purpose is to first determine how fast you would like for the stone to cut and how fine an edge you need, and then choose either a soft, coarse, stone or, a hard, fine, stone of the appropriate type and grit.

The video above, from the How To You YouTube channel, explains everything you need to sharpen with a whetstone at home, and the best methods for doing so. Obviously, you’ll need a whetstone (as well as a few other things), and you’ll want to work near your sink or a bucket so you have easy access to water. Fill a container with water, then soak the whetstone in it until it stops bubbling. Inspect your blades for any trouble spots, and get to sharpening using the methods and motions described in the video; making sure to check your progress as you go. We’ve talked about sharpening knives with whetstones before, but this guide is a bit more thorough and the old video has since been removed.
These are unquestionably great starter stones. After all the sharpening done over the course of a couple days, they're still perfectly flat, showing little to no signs of wearing down. Mind you I did watch tons of how-to videos online before undergoing the endeavor, so I knew how to try to make the stone wear evenly. But, my 15 year old nephew who was working on the Ontario, as I told him he could have it, if he wanted to fix it up, didn't watch all those videos and I didn't see any uneven wear on his stone after working it about a half hour either.
I really liked this whetstone! I had a Smith's pocket sharpener that could get my knife sharp enough for working around in the yard (I have an Opinel no.8). However, in doing a little research I found that the sharpener was only around 600 grit on the finest setting. So this BearMoo 1000/4000 grit looked like the perfect step up, and it turned out to be the perfect stone for me. The pictures are an accurate representation of what you get. The removable rubber base was helpful when switching from one side to the next, and it kept the stone from sliding around. The instructions say that the stone can work with either water or oil, but that water is preferred. It said to leave the stone soaking in water for five minutes, and the stone worked like a champ. I especially liked how the instructions gave you an approximate time of how long the stone takes to sharpen a knife -- it just helped give me an idea that it would take about 15-20 minutes on the 1000 grit side, and then another 10-15 minutes on the 4000 grit. Just turn on a TV show!