Well I finally got a spine and went with the Behringer V-Amp Bass Pro.
I wired it up digital direct to my DAW and gave it a whirl.
First thing I checked was the highly acclaimed Ampeg SVT emulation and as far as I'm concerned that one sound is worth the cost of the unit.
First negative so far, envelope/filter based effects (auto wah, Ultra-Bass, Voc,Vcr) are extremely noisy/breathy. In mid play it's not noticable, then stop and...whosh!!!
I'll hopefully do some tracking with it in the next weekend or two to get a real world feel for it.