Both are great amps, need some more info like what ohm are you wanting to run what is your budget, are you talking the old or new M3 and is it the AQ 3500 or 3500.1 and what type of actual power are you wanting?
well daily since i really though about it for like 15 minutes go with the dd cuz it looks alot smaller with a big punch and probly wont be draining ur car that much when u do play it loud
the m3 is superior, but by no means are the AQs bad.. whats your budget and whats your electrical system like? the AQ has a more dynamic power consumption while the DD draws less current but its more constant.. so it depends on your electrical system...