real simple. jl audio 300/4 or phoenix gold octane r5.0:4 (also is that amp 80x4 at 14.4 volts, cus i have like 13.9v) which one is better quality, features, and sound clarity.
Either really, both make excelent amps. I do like JL a little more do to the fact they can put out the same amount of RMS power at 12 to 14 volts no matter what ohm rating you have the speakers wired at.
One of the biggest drawback with JL is their price. It is a good amp, but for the money they're asking, I'd rather spend that on Zapco. This is the reason why I don't own JL amps.