It depends on which one you get. The original and the reissue are good, but the others (like the II, the Bass Whammy, and the XP100) suck serious tone. For the money, I think the reissue is pretty darn good, and you don't have to blow $400+ for an original that uses pretty much the same guts.
I've tried them all, and I dig the reissue the best. The pitch shifting is smooth, yet retains a gritty digitalness that is kind of the hallmark of the unit. Sure, you can get flawless pitch shifting with a G-Force or something, but that isn't as much fun for some reason. You need a pedal that makes your bass sound like a gremlin. Mostly they track pretty well once you get above the 5th fret, but below that, it's just digital mud; which is kind of cool.
