I need your opinion on which sub is better?

woah woah woah.... hey there buddy, MTX is a very good name brand. my whole audio system is MTX, and ill tell u what, they take anything you throw at them. they are very durable subs. i would go with the MTX simply because the quality is way higher than polk audio subs, and after time, you will be able to know the difference... i have speakers rated for only a couple hundred watts, and i just put an amp on them that was rated 1000w rms (MTX jackhammer amp) and they handled it with barely any distortion. i just wish i had the money to buy the amp from the guy. so, i would definetly go with that MTX setup.... and maybe later get a bigger amp.