The 1200.1 might be good, but you have to realize that the 12w7 is a 3 ohm subwoofer. At 2 ohms this amp puts out 1200 Watts, at 4 ohms it puts out 600 watts, so at 3 ohms it would put out somewhere between theses values. Someone here probably knows the exact number, but I'm not sure.
I woudl say that 600 + RMS power would be pretty decent for the 12w7 for regular listening.
The 500/1 is a good amp, and it puts out the 500 watts RMS at 1.5-4 ohms, so you will get the power for your speaker.
Good luck!