Last night I decided to formally compare all my cabinets using the same amp (Demeter VTB-201, BBE DS24, Crown XLS 402) and bass (honestly don't remember which bass I used). Sorry, no sound clips, too lazy to properly mic everything. But here were my opinions:
Acme Low B-4 (series II):DEEP. Tons of low end, but a very "flat" sound overall, thanks to the 3-way design. Sounded pretty uncolored (much like hearing a direct bass signal through nice headphones or studio monitors). Quiet, needs a lot of watts. I should also add that the bracing on these is INCREDIBLE (no "ring" when tapped with knuckles).
Acme Low B-2 (series I):Not as much low end as the B-4, since it has half the woofers, but overall a pretty similar tone.
Avatar 2x10: (non-neo I believe, speakers are Eminence Deltas)
VERY loud tweeter. Tone overall emphasized the high mids and highs; lows were lacking (which is somewhat to be expected of a 2x10).
Carvin BRX 4x10 Neo:Emphasis on the low mids. Deeper than the Avatar, but didn't go as deep as the other cabs. (Although they quote something like 20Hz on their site.... 
). Not as much upper mids or highs as the other cabs either.
Carvin Redline "Cyclops" 15+2x8+t:Massive and heavy combo amp. Never really cared for the tone. But when I ran my Demeter rig into the cab portion using the DS-24 to biamp (the 15 has a separate input from the 8's and tweet, with no internal crossover), I was very pleasantly surprised. Tone was similar to the Acme B-2, but a little "dirtier". Not as much lows as the B-4 though. Also suffered from horizontal dispersion more due to the arrangement of the mid drivers. When run full range instead of biamped, sound was about like the Carvin 4x10.
Overall:
The Acme's have an awesome tone. But, they need a lot of watts to get loud, and I already noticed some speaker buzz when I push them (seems like lots of people have had to replace the drivers.) I may stick a poweramp where the R1000 head is in the combo and use the cab with the Demeter and BBE in a small rack for most of my gigs.
Also, I'm expecting a fEarful 12/6/1 in the mail soon, and may build a BFM in the near future....
