The RBI (as far as I'm aware) uses the same circuitry as the Bass Driver DI.
I mostly use studio-owned Ampeg SVT Classics for rehearsal, but have to rely on whatever I can get for gigs (because I have to rely on public transport, my rig stays at home).
On Saturday's gig I borrowed a Peavey rig (not sure what model) and it pretty much sucked. Horrible nasal tone, couldn't get much else. Stick the Bass Driver in there and I instantly managed to dial up a very passable SVT tone. I'd be happy to just use it as a DI, but I like to have an amp on stage.
It turned out to be one of the most enjoyable gigs I've played, it was packed out and the crowd went nuts.