Good choice. I'm not knocking the 350, but for the difference in price the sonic performance jump to the 500 is huge. About the only thing those subs have in common is that they are made by Axiom, use 12' drivers, and reflex alignments. The 500 has a 500w digital amp compared to the 200w amp in the 350 so right there you will have a big difference in sound quality with less distortion on the 500. The 500 extends 8hz deeper has 2db more max output. The 500s DSP controlled frequency response will mean more linear output than the 350. It is a killer sub in all respects. I have yet to hear a 12" sub which sounds as good, except for the 600 and the Velodyne DD12 subs.
