Is Heat Public Enemy Number 1 ?

[Einar72]

Fan without filter = dust buildup. It's easier to filter the air going in than fishing dust out of everywhere, so a pull-through fan on the hot end of the cabinet would not be my first choice. Use your PC as an example; pulling air out fills every crack, crevice and drive opening, and it's pretty fine particles usually. Choose the in-flow location carefully, and you'll be breathing extra years of enjoyment into your precious roundie!