well i just finshed with installing my deh-580mp, and all i can say is wow, i know its not the best but it is fvckin awsome, the eqs are great, i adjusted everything with my new alpine speakers and it sounds so so so much better than my old setup, i can't wait till i get my subs hooked up, it'll sound even better, this is by far a great hu for only $150, just figured i would tell every1.
the HU will determine how everything else will sound. if its crap, it'll send crap to your amps, which will amplify the crap and your speakers will reproduce the crap. lol