Which of these two sub/amp combo's are better, and WHY?

Hands down, I would take the Rockford Fosgate amp. But the 12" subs are twelves, and the tens are tens. I don't know about either of those brands for subwoofers, but I know Kenwood is also a decent brand of audio. Also, you have to consider the specs. You didn't say how many watts the amps are, or the twelves, and you didn't say how many ohms the subs are. There is a lot to consider, I can't take the info you gave and say one combo is better than the other. But I can say that most people say this; Having a cheap, crap, no name amp with 1000 watts is kinda pointless, it would be better to take a good, quality 500 watt amp like Fosgate. I would probably take the best amp, cause you can get good subs anywhere, even a pawn shop.