Peter Erskine's got one too, although his sounds different from mine (go figure). You can see it on a couple videos here as well. They can be quite obnoxious if you aren't careful. I think the best one though is the Bosphorus Jeff Hamilton model with just the three rivets. I think the excessive rivets weigh the cymbal down and decrease the sizzle potential.
I also have a 20" Zildjian Swish Knocker that I picked up in a local Kijiji deal. The cymbal produces quite a punch, with a good sustain. I don't use it often, as I my kit has 2 different Paiste rides. I might deal it in the future.