By late May I plan to be running a RC8B3e at GFX. With the RC8B3.1e just announced but not available yet (late May) the RC8B3e is available used at some good pricing as others upgrade.
I can't add much else (never ran one yet!), except to say I looked around and the reviews are pretty good and of course parts are easy to get. Most say its a copy of the mugen which is probably a good thing.
Tekno is the "popular" brand at GFX at the moment, but I'm going to buck the trend