To make things simple: Rockford is a overall more solid company. There products are of the highest quality and are usually underated. MTX is more of a medium quality company with some good equipment on their higher end line. Rockford is quite expensive, but you get what you pay for.
overall, couldnt tell ya, but I lean towards RF. their amps are good, but when it comes to subs only the 9500 would be worth it for me, as for RF... none of their new line I would sample not even the t2, their old Hx2's were good.
RF FTW, both tested 9500 and t2 and imo i like the rf... have used a 10001bd ona type r 15 and it was a solid amp... that amp has been passed down the line and it still kicks everyday.... mtx.. good stuff, but dosnt compete with rf... imo