I use only Japanese water stones. I have tryed all the rest, and for my tast didnt like them. My bigest complaint with dimond stones was the little holes. I didnt like the feel of how the blade edge ran across them. Expecialy at the tip. I also didnt feel atall comfortable with there thin profile. Both issues are personal tast.
On a plus note for dimond, thin light profile, very easy to keep with you. Almost no maintanace time.
Negative on all stones, larger thickness and more weight. Also stones like Japanese water stones are VERY suceptable to breakage due to temperature. If you leave your water stone saturated and the temp goes bellow freasing, chances are you have just broke your stone. And after some time using stones they should be trued.