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+.
Some experts recommend sharpening as if trying to slice a thin layer or decal off the stone. Don't consider doing this without significant experience: it is typically bad advice; most people don't hold the correct angle this way. You instinctively raise the blade until you feel and see the edge working. This creates larger edge angles and thicker bevels as time goes on and the results gradually deteriorate. The more you sharpen, the duller it gets. Sound familiar?
Not sure why I bought this item and then I received it. It has a bit of a 'cool' factor and is well made. I took the sharp edges of the stone as they were a bit uncomfortable on my chest but have since been wearing it a lot. Used it to put an edge on some workmates knives and to tickle up my own daily use knife. I like it, it is a bit different and useful.
The composition of the stone affects the sharpness of the blade (a finer grain, usually, though not always, produces sharper blades), as does the composition of the blade (some metals take and keep an edge better than others). For example, Western kitchen knives are usually made of softer steel and take an edge angle of 20–22°, while East Asian kitchen knives are traditionally of harder steel and take an edge angle of 15–18°. The Western-style kitchen knives are generally in the range of 52–58 on the Rockwell scale, which denotes the relative hardness of a material.
It is sometimes too confusing on understanding the right sharpener that right to our tools. Then using the chart above you can consider on what is the right stone. Green, red, yellow and blue line they consist of the most familiar and affordable models of sharpening stone to purchase. You can see the performance of each stone in the chart. Silicon Carbide, Aluminum Oxide, and Arkansas they are typically used with the oil (Oil Stones). Waterstones (Synthetic Waterstones) are generally made of Aluminum Oxide too, then people also use oil in place of water with their Waterstone or use water on their Silicon Carbide sharpening stone in place of oil. In this group, Waterstones is the most preferred because of its easy for sharpening edges in shorter time.
As opposed to water whetstones that require you to pre-soak the stone, the Norton oil stone is pre-filled with oil to save time and eliminate the need to pre-soak it prior to use and the lubricant stays on the surface during sharpening.  The oil also prevents metal from bonding with the abrasive surface by flushing away dislodged abrasive and metal chips.
Now you may wonder, if a finer stone produces a better cutting edge why do I need a coarse stone at all? The answer is that finer stones work much more slowly than coarse ones. The amount of metal a fine stone removes with each pass is much less than what a coarse stone removes. If you have an edge with a good shape to it from a coarse stone, this is not a problem because the fine stone doesn’t have to remove much metal to improve the edge. If the edge is dull, it will take many times longer to reshape it with a fine stone than it would with a coarse one.

Sharpening on the other hand is reupholstering the furniture or telling the hair stylist to give you a new look. Material is going to be removed from the edge of the blade. There’s no way around it. How much is removed will be a function of just how dull the knife has become or whether you’re sharpening to compensate for a chip in the edge or because the tip has broken off. If your knife is not damaged and you have it sharpened twice a year very little material will be removed each time, yet it may still be enough for you to notice just by looking carefully with the naked eye.
Oil Stones differ from water stones in that they require the use of honing oil to float the swarf (metal particles). Also, these stones are commonly made from one of three different materials consisting of Novaculite, Aluminum Oxide (Corundum), or Silicon Carbide (Carborundum) and they all use oil to lubricate the stone and suspend the swarf in order to prevent the stone from becoming clogged. Also, while Novaculite and Coticule are the most traditional types of oil stones, there are also synthetic oil stones made by the Norton abrasives company called “India Oil Stones”.
I've used ceramic rods, diamond plates, and leather strops for our sharpening needs. And, like most, I've tried a dozen little gimmicky sharpeners that, while some work, those that do often remove way too much material from the edge, making your blade wear down faster. I've also used oil stones, grinders and buffers for less meticulous sharpening of axes and such. These two stones from Unimi (600/1000 and 2000/6000) served as my introduction to whetstone sharpening. And I must say I like it. Though, I'm not sure of the need for investing in more expensive stones.

To summarize, Shapton Glass 500, 1,000 and 2,000 is a good combination and if you would like to throw in the 4,000 grit stone in lieu of the 2,000 that is good as well. If your knives are very hard, ZDP 189 for example, this is a fantastic choice. (They are also excellent for tools, chisels etc. and they are the premier choice for many Straight Razor honers).
This is a great sharpener for budget conscious cooks. You can use it with equal facility whether you’re right or left handed, it has a convenient finger guard to cut down on accidents and most important, it only takes a few swipes on a regular basis to keep your knives in tip-top condition. It’s not glamorous. It won’t add anything substantive to your kitchen decor. But it will ensure your knives are always ready for whatever dish you have in mind.
Put the pointed, narrow end of the sharpener up against the open end of the gut hook. The narrow, pointed end of the sharpener should face in toward the thickness of the blade, away from the edge of the gut hook. Match the angle of the sharpener to the original edge angle. This will maintain the correct sharpening angle and prevent you from getting cut by the blade tip. Hold the same angle when sharpening each side of the gut hook.
Steeling helps maintain sharpness. This process realigns the edge, correcting for dulling causes such as a rolled edge. A sharpening steel is a type of hardened cylindrical rod used similarly to honing stones. For example, a butcher steel is a round file with the teeth running the long way, while a packer steel (used in the meat packer's industry) is a smooth, polished steel rod designed for straightening the turned edge of a knife,[7] and is also useful for burnishing a newly finished edge. Because steels have a small diameter they exert high local pressure, and therefore affect the knife metal when used with very little force. They are intended for mild steel knives that are steeled several times a day, but are not well suited for today's tougher and harder blade steels. Diamond steels are now available that have an industrial diamond coating and can remove blade metal as well as straighten, therefore used correctly they can re-profile a knife instead of just honing.