I have used the Outlaw 990/7125 combo for about one year. I know that you are not as interested in 7-channel amps, but this one will power anything Axiom makes, and you could get this combo cheaper than a 4306, IIRC. Mine is hooked up to an Epic 80/500 system in 5:1 in my home theater and a pair of W3s in my hobby room.
I've got the components in an Ikea glass-front cabinet and cut out most of the back for ventilation. I've never had to use a fan, as they run warm, never hot. I've listened to movies as loud as the wife would let me (-25dB). I've briefly listened to music at 0 dB, but extended play at -20 dB is more frequent and not a problem on the system or my ears.
I'm not qualified to write audiophile reviews, but to me the sound is clean and detailed. The sound stage, if I'm using that right, is really impressive on SACDs and DVD-As, where I would swear that I'm at a live performance.
I'm sure that the monoblock guys will chime in soon ...
