I don't think combo boxes like the USBPre or the V3 used as preamps only stack up against preamp only boxes like the V2 and Sax anyway, to be fair.
Ok, threadjack I guess (especially since I haven't listened to the comps):
I can't comment on the USBPre since I haven't really listened much to one, but I'm curious about your V3 vs V2 comment. I can see how the V3 A/D might not be worth it to some (many?) or that it was an add-on to what is essentially a preamp, but why do you think the V3 doesn't stack up to the V2 as a preamp?
Mike Grace said they are essentially the same thing as a preamp (other than one is surface mount vs thru-hole, and use slightly different Burr Brown instrumentation amps since the earlier one had been discontinued I believe before the V3 came out).
Other than those changes and some changes to the gain structure, I thought the V2 and V3 were pretty much the same preamp.