Certainly a weird one, doesn't really capture your sound in it's true form, so if that's what you're after it's not really for you.
But if you like the chimey polyphonic sound, then it's really cool. I'm ALWAYS nicking my brothers, which i use mostly for solo stuff or a soundscaping duo I'm in (thankfully, with said brother haha!)
Useful for Bass? Well, down to how you use it, but I like it and have lots of fun with it, I use it a fair amount for completely unaccomanied stuff when doing more abstract stuff.
Tried it with the band and it wasn't really too great for that (just my experience anyway! Playing rockier stuff to heavy stuff) due to that sort of Polyphonic sound, maybe in a thick mix the chimey-ness and overtones wouldn't be as much an issue? Kept sticking out to me though so I turned it off pretty quick, and it didn't play well with the Distortion stuff I was doing, (which I use 90%) but that was probably more me than the effects.
Love the things though, would love to have 2 Super Egos, or a handful of Freeze pedals.
Scott Fernandez (top chap! 12 string bass player (ERB)) uses them a lot (the freeze pedals) if you want some examples! Just look him up on youtube