Between Florida Arcade & Pinball Expo, ReplayFX, and Modern Pinball NYC I would say I've played around 20-30 different ones. Right now at MP they have a Sonic Prospector which I think plays very nicely, not really sure which is my favorite however. They are indeed a nice change of pace, but with some of the improvements seen in modern machines, they can get frustrating at times.
I wish I could play more.