I think these amps are awesome considering they are lower wattage amps. I have the 351m wired to a JL Audio 12w3v2 and the 551x wired to Inifnity 3-way coaxials (6.5" and 6x9) and these amps are great. They compliment each other, and the amps are relatively small. They look nice with their blue glow for the RF logo, which adds some style to an enclosure. I have the 351m wired to 350 watts at 2ohm and the 551x wired to 70x4 watts at 4ohm. Power is 4g to the 1 farad cap, then to a distribution block, then 8 guage to both amps, then 4g to ground. I also payed a decent price for these two subs. I got them both used, due to the fact that they are 2003 models and discontinued. The 551x was 160, and the 351m was 130. I am very happy with the way these amps compliment my components, and vice versa. These are actually the first amps I've ever boughten, but I've heard many different amps from friends and audio competitions, and I am very happy with these. The small wattage powers my components just fine.
I'm not as in depth as a lot of the other guys on this forum, but I hope this helps anyone out there.