The following are my personal favourites and they are all synthetic stones, I do have experience with natural what stones but lets keep it simple, lets stick to synthetic water stones. Believe me, some of the world sharpest knives are sharpened solely on synthetic stones. Here are my personal favourites, I use these water stones every day and the order is not necessarily in priority, they are all good.
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.
The final Chef’s Choice sharpener on our list is the 316 Diamond Sharpener. Like the 15XV the 316 is at its best when used to sharpen Asian-style knives and it does so with unflinching effectiveness and speed. This is a compact, 2-stage electric sharpener that produces the 15 degree edge so favored in Asian cutlery. Ideal for the preparation of sashimi or sushi.
Aluminum-Oxide oil stones are very popular man-made sharpening stones produced by an abrasives company called Norton and which are commonly called India Stones. Generally less expensive than Arkansas stones (aka Novaculite), these stones are graded coarse, medium, and fine and are designed for fast cutting. Yet, when the fine grit is used, they can also produce a relatively fine edge. Also, because India Oil Stones are both softer and coarser than Arkansas Stones, they are commonly used in conjunction with Novaculite to cut the initial edge bevels or, repair extremely dull or damaged edges before refining and polishing the bevel with an Arkansas Stone.

However, because the Belgian Blue stone generally occurs in relatively wide columns with much thinner layers of Vielsalm Coticule on either side adjacent to the slate, the Belgian Blue stone is more plentiful that Coticule and thus, it’s somewhat less expensive. But, it’s also somewhat softer than Coticule and is not divided into different grades as Coticule is. Furthermore, because it is a softer stone than Coticule, it is sold without a substrate layer.
"How do I use this daunting metal rod?" I hear you ask. Well, it's not too hard, really. The best way for a beginner is to balance the steel on a surface with the tip secured by a damp tea towel. You want to get that angle right, whether it's around 15 degrees for a Japanese knife or 20 degrees on a German or French blade. Then swipe slowly down, away from you, making sure the whole blade is honed – around five swipes on each side should do. 
I purchased this set together with the 400/1000 grit stone assuming that some of my knives were quite dull and would need work on a coarse grit stone. Premium Whetstone Sharpening Stone 2 Side Grit 400/1000 | Knife Sharpener Waterstone with NonSlip Rubber Base & Flattening Stone. This is my first wetstone. First off I tried to sharpen my Chicago Cutlery boning knife. This knife is nearly thirty years old, has been abused in may ways and was quite dull. It was very difficult for me to get a burr on this blade, which I attribute to poor technique. Next I moved on to my Henckels Professional S paring and chef's knives. The paring knife was moderately sharp and was modestly improved after working over all three grits of stone. It would cut paper but again it was difficult to develop a burr with this blade. Undaunted I switched to the chef's knife. This knife is twenty years old and has never been professionally re-sharpened. I have sharpened it twice with a Lanksey sharpening system which marred the finish but did put a good edge on the blade. Lansky Standard Coarse Sharpening System with Fine Hones. The chef's knife was moderately dull and had several pits visible on the cutting surface. I modified my technique for passing the knife over the stone and worked the chef's knife over the 400 grit stone aggressively and eventually I was able to get a burr to form from the tip of the knife all the way to the handle. From there it was a simple process of reforming the burr on the 1000 grit stone and then finishing on the 6000. After sharpening, the chef's knife easily and cleanly slices a tomato with very light pressure and is in my opinion very sharp. Not sushi knife sharp but more than enough for the chopping and slicing I expect of it. I'm looking forward to going back and working both the boning knife and the paring knife over again. Don't expect a good result from this product the first time you use it. Watch videos on using a wetstone, expect to spend at least twenty minutes per knife at first, and practice forming a burr. If you can form a burr, you will be able to successfully sharpen your knife.