I have a DMT dia-fold (fine/extra-fine) with magna-guide and the DMT aligner 4 stone kit (4 x 4" stones, extra-coarse, coarse, fine, extra-fine) with aligner. I also have a 6" coarse stone for free hand and re-profiling.
The diamonds don't wear fast, they sharpen fast. You only need light pressure to remove metal.
They work well, I'd buy them again. I'm looking at adding the Extra Extra fine stone for the aligner kit. It's suppose to be around 8000 grit, which is the same as the Spyderco Sharpmaker Ultra-fine rods (which is guessed at being around 8000 grit).
I still think the Sharpmaker w/DVD give the best bang for the buck in a simple, usable sharpening setup... that being said, the DMT stuff is great, and most folks with a Sharpmaker will end up either having to buy the diamond stones for the Sharpmaker or a DMT bench stone for re-profiling or fixing a damaged blade, so there isn't any reason you couldn't just use the DMT stuff.
NOTE: 2009 is the year of acquiring the skill of sharpening for me, so I've been studying faqs, buying books, and testing equipment. I'm left with testing paper wheels and the ol' harbor freight 1" x 30" belt sander with lee valley belts.
