It will work just fine. But for that money, you would be better off using two amps. And you can do that for under 500. One class a/b 4 channel amp for the towers and any interior speakers and one class d for the sub(s). I am using car audio amps. They need to be protected from water and should have some air flow for cooling them off. I would not spend my money on marine amps.
As far as amps to look at, Hifonics, Kicker, PPI, Alpine to name a few.