the 2 12s have the sligth advantage in cone area, but the 9500 is built for larger boxes and higher tunes AKA output..
its going to be a more narrow bandwidth but it has to potential to be peakier and louder even with 1500..
1500 in 5 bubes with 50in^2 of port area will make it sing..
the SA has a high MMS and a high Qe its gonna have a smoother sound to it and a wider bandwidth but will never get peaky like the 9500.. the 9500 has about 2x the motor strength and nearly the same mass as the one SA 12..
i dont understand why someone would say it has more motor strength.. motor strength alone is irrelevant..