I have been using one of those titanium diamond plates from 330mate and it seems pretty strong. The 300/400 side is aggressive and the diamond pattern (of blank areas) helps avoid build-up. The 1000 side is nice for light surface prep on my jnats... at least so far.

I have also been abusing it with my homemade metal creations and although I have worn off some areas at the edge, I like it.