Had a good chance to play with this today, here are some thoughts:
Overdrive - BB Preamp sounds reasonably close to the real deal, with the added feature of a clean blend. The Boss ODB-3 sim is not far off either although has tone control instead of active hi/lo eq so doesn't have the same monstrous lows. The Bass Big Muff is also great, adding features to the original of a proper blend control and the ability to have the bass boost mode on with the bend simultaneously. The Sansamp BDDI is pretty good too. The rest are pretty meh.
Filters - the Q-Tron and Moog LPF are excellent, although I can't get the expression control to work very well with them. Perhaps I need a real Zoom pedal instead of my Moog one, I'll have to look up the specs.
Synths - Mostly garbage except the G5 clone which has flawless tracking and a very usable sound. Never heard a real G5 to compare though.
Compressors - The are surprisingly good, I remember them being useless on the B2. They fatten up the tone nicely.
Amp Sims - Only had a quick go of these through headphones, will try through the monitors tomorrow. They seem pretty average overall, most are clean, the SVT / B-15 / Bassman can get a bit dirty but can't do a heavy overdrive. The B-15 sounds nice when pushed for a fat round Motown tone.
Only had a brief spin of the delays and modulation but they seem ok. With the looper, tuner, drum machine, USB audio interface, DI output etc this is a bit of a bargain unit