I am facing the same dilemma.
From what I understand Chieftec cabinets have fan cooling from the sides whereas the CM Elite 330 has a giant 120mm front facing fan.
Chieftec cabbies do not have filters but the front grill of the Elite 330 does, though I hear it is a pain to clean.
I would prefer Chieftec, it looks to be roomy and better build quality. Does anyone know if there is a Chieftec cabby with a front facing fan?