one of these days, I'm going to sell a kidney, my mp-2, and r-1, and pick up the V3/MT combo. I don't think there's much out there that can top that in the price range... this of course is just from the tapes I've heard, etc etc.
Wait, you say you want to sell your kidney to buy a V3/MT combo. Lay off the booze and your kidney would be worth a portadrive.
All this talk about V3 vs. ACM 671....I say location location location.
I have recorded with my 660 vs V3, most of the time my friends V3 sounds slightly better but if I'm in the sweet spot he wants my recording. We usually matrix his stealth km54s>V3>D8 audience with my SBD>ACM 660 and it's all good.
I think the difference you're hearing between each others recordings is the microphones. I don't think a good comparison of the 660 and V3 can be made until a test is done with the same or comparable mics.
AKG 31 (mini mic) freq range 50-20,000
Neumann KM54 (tube mic) Freq range 20-20,000
EDIT: To add, even the 184s will sound different than the KM54s. Tube mics are a different animal than what most are using here.