Dust is not the problem. All intake fans have a dust filter on them (and would use them in the new case if it dosn't come with them). I clean out my dust filters at least once a week and about once a month I blow out the dust from inside the case I live in a house with a few cats... if I dont clean my pc like an OCD freak ill blow up GPU's and PSU's like crazy...been there done that lol
Looks like the CM case is the better choice right now. Im still on the fence about the cooler... Could it be I'm using two low end fans? I swaped out the stock CM fan for 2x CM Blue LED fans.
They really shift some air, nice heavy build quality, and not even that noisy (I've had worse ones rated more quietly) and they're cheap as chips...