My experience with DMTs encompasses quite a few plates but I haven't really used that exact one. As far as anecdotal evidence goes, my dad likes them, especially for steels like S30V and INFI. In general I love diamonds for flattening my water stones and love the way the coarser DMT Diasharps work as aratos for setting bevels. I do nearly all of my flattening with a DMT XXC, with the rest being done on wet/dry sandpaper or a drywall screen over a granite reference plate. Kudos to BDL, btw, for that last suggestion.
One knock I hear repeatedly is that diamond sharpeners wear out too fast due to the diamond particles been pulled out of the matrix that holds them. I've heard this from many people that have more experience with them than I do, but I'm agnostic about it. I've never seen it, and I have DMTs that have been used heavily for years and they still work well. Others have reported wearing them out very quickly. I know that some sharpening systems like the Lansky and Wicked Edge rely on diamonds and have a loyal following.
I will say though that very few people report problems with them as flatteners. BDL has a friend who eats the things for breakfast but I think he's an aberration (and I suspect he just leans on 'em too hard). On the plus side, the DMTs will never dish. It's great to have a flattener that you don't have to flatten periodically. And in my experience they last a long time. On the minus side they're kind of expensive. For the 8" DMT XXC any price under about $75 is a good deal.
BTW, if I wasn't clear I like the DMTs in the lower grits (XXC, XC & C- roughly 120, 220 & 320) but I just use Japanese waterstones (both natural and synthetic) at the other grits. Outside of DMT I have very little knowledge of other brands of diamond products save the spray stuff from Hand American.
Okay I was windering if the D8EE compares to a waterstone of similar grit levels -- it's not expensive relative to the waterstones of a similar grit, and from every desription it works faster.
For the lower grit plates, aside from losing abrasive power (which as you said might be a problem with the way in which it's sed), I also read in some online stuff that while diamond plates work faster, they also leave deeper scratches. Have you found this to be the case?
I flattened my King 1000 with 120 grit drywall screen (didn't think to get the wet and dry version and so went through a 3-pack very quickly). The rest of my stones are still relatively new, but I certainly want to keep them flat, and I was looking at the options.
Right now my stones include:
2 Aotos, 1 between 2-3000, the other between 4-5000, estimated)
It seems that I ended up with the two stones being sold under different grit numbers. Neither is labeled with grit numbers on the packaging.
As of now the King 1000 is flattened. The Aotos show a slight dish, and the Takenoko and Kitayama don't show any visible dish yet. I would like to use the least abrasive grit I can get away with, and was wondering if 600 or even 1200 would work to flatten the higher grit stones, or would I need to go coarser or finer than that. The diamond plates seemed like a good solution because they have a reputation for working fast at removing material, but I wanted to hear if you guys thought it work or be counterproductive to use coarse paper or diamond plates on the finer grit stones?