I read in FUZZ (a Swedish mag.) that they considered AC-3 an improvement over AC-2. However, as a satisfied AC-2 owner I tested AC-3 in a store with various guitars (yes, I know single coils should be used) on a Roland amplifier, and I couldnt get a single usable acoustic sound out of AC-3. I didn't test the AC-2 alongside though. I have read on Harmony Central that it has got bad reviews. Maybe you have to connect the second output to a dedicated full range system (while staying on the guitar amp with the other output) to make this one shine. AC-2 does sound acoustic through my 4*12 though. Both have very low acoustic volume levels.