Heres why I wasn't impressed at first. I only used it for a few minutes on each side, which resulted in nothing. I watched a video online with a master chef using his stone, and he sharpened his knife for 10 minutes on each stone before moving up to a finer grit. I took this hint, and used sharpened my knife on each side of this stone for 10 minutes, which led to perfection.
Water stones can also be made out of natural or synthetic materials and they are fast becoming the most popular type of whetstone as they only require the use of water to lubricate the stone. They are not as messy to work with as an oil stone and deliver fast sharpening results but for even better results, soak the stone in water for 5 or 10 minutes.
The smaller the angle between the blade and stone, the sharper the knife will be, but the less side force is needed to bend the edge over or chip it off. The angle between the blade and the stone is the edge angle – the angle from the vertical to one of the knife edges, and equals the angle at which the blade is held. The total angle from one side to the other is called the included angle – on a symmetric double-ground edge (a wedge shape), the angle from one edge to the other is thus twice the edge angle. Typical edge angles are about 20° (making the included angle 40° on a double-ground edge).[1] The edge angle for very sharp knives can be as little as 10 degrees (for a 20° included angle). Knives that require a tough edge (such as those that chop) may sharpen at 25° or more.
Now it's time to polish. This is when you'll swap over from the coarse grit to the finer grit (make sure this side is wet, too). I found the knife still had a bit of grime on it, so I gave it a wipe clean beforehand. The motion is exactly the same as with sharpening, but you can apply slightly less pressure, and limit to roughly 30 strokes on each side. 
This 600/1,000 grit is my second Unimi knife sharpener, the first is 2,000/6,000 grit and I love them both. Both stones together produce very sharp and well polished knives that reduce the cutting effort and save time in the kitchen. I particularly appreciate that the manufacture printed the grit number on the side of each stone - that helps use the different grits in the proper sequence from the coarser to the finer. The stone comes with a non-slip silicone/rubber base which is very handy.
Our large selection of stones from many well-known manufacturers will allow connoisseurs to find the ideal stone for their needs. Because all manufacturers formulate their stones to emphasize a different mix of qualities, and because these qualities can vary widely between different stones, most woodworkers choose stones from several manufacturers to build up an optimal set of sharpening stones. Then again, once you get to know the characteristics of certain types of stone, you may find one supplier who will provide all the stones you need. Sometimes this can be an advantage. But there is no one size that fits all; each stone must fit your needs and work style.
An extremely well written and informative article on sharpening. Overtime we all get to love certain stones for our sharpening needs. I am a huge coticule fan, and although i have used all the others, i always come back to this natural stone above all others. Still trying to figure if i chose it or it chose me! NEver the less there are so many options out there it is not hard with a little time and effort to find the right combination for your needs.

If you don’t have a problem with the water-lubrication system in your working environment, Waterstones is the most common and affordable models to obtain. They are available in various abrasive grit grade from coarse to extra fine mesh. They generally made by Aluminum Oxide, which provides faster cutting. The downside of the Waterstone, they wear down more quickly as the impact of the old abrasive materials that break the stone itself. It is why Waterstone requires frequent flattening to keep it evenly. It is recommended you have one of diamond stones to help you for regular flattening become easier.

You’ll know you’re reached a stopping point when you can feel the slight catch of the bevel on the edge of the blade, by carefully running your finger in the direction of the blade, or by cutting through a sheet of paper. When the knife cuts cleanly through the paper, it’s time to hone the blade. Read our guide for more information about honing vs sharpening.
But it's a different type of sharp, according to Joe Authbert, product development manager at ProCook. "What it does is add tiny little micro-serrations onto the edge of the blade." But fear not - your smart knife won't end up looking like a bread knife, as you'll be hard-pressed to spot the serrations. "If you looked at it under a microscope, on the cutting edge, there are these little lines that generate the sharpness, rather than a waterstone which is a smooth sharp edge," says Authbert. 
Like all DMT® products, DMT sharpening stones are proudly made in the USA and will produce excellent, consistent results time after time, year after year. DMT's diamond sharpening stones feature the most diamond per square inch in the industry and a proprietary process that ensures near-perfect consistency in grit size, engineered to be the flattest sharpeners on the market. Simply put, DMT’s premium sharpening stones are best-in-class products with undeniable long-lasting value.
I recommend keeping two stones in your kit. One with a medium grit (around 800 or so) to perform major sharpening jobs, and one with a fine grit (at least 2,000) to tune the edge to a razor-sharp finish. For real pros, a stone with an ultra-fine grit (8,000 and above) will leave a mirror-like finish on your blade, but most cooks won't notice the difference in terms of cutting ability.
Some of the videos I watched suggested soaking the stone for 12-15 minutes prior to use. One suggested using vegetable oil on the surface versus water/soaking (I used water and presoaking it for 15-minutes). So instead of a simple 'out-of-the-box-and-use' approach, it required a bit of research before sharpening a knife. Otherwise I would have given this product a 5-star rating.