That was my thought as well. With the top down, there's going to be a hot spot between the PSU exhaust and the radiator, I think, as the air flow may not be as strong when it moves through the fins into the case.I know some people have been discussing ventilation etc... hot air does rise, but slowly, and forced air goes in the direction of the fans following the enclosed space. However any change in direction or obstacle in its way slows it down, so exhausting air out the bottom will result in somewhat slow moving air all around the case, which might get re-circulated back through the top, if in a room with stagnant air anyway. If you're doing that I would place it in-between the supply air vent and the return for the room to get cross ventilation.
Exhausting out the top will throw the hot air away from the case and let it continue rising up and away.
Also, has anyone tried putting the NZXT logo right-side up, with the hoses at the back? Are they too short?
For water, I believe by design of the case, the hoses have to be up front. I think Sliger stated that somewhere.That's sort of what I'm wondering with the Corsair H100i I was planning to use in my 580- most builds/pictures of the 570/580 have the AIO hoses coming out on the left, nearest the memory. Is there any reason you couldn't orient the AIO so that the logo is right side up with the hoses coming out towards the right towards the back plate and just winding them up to the radiator? I'm guessing that's just a question of tube length/flexibility?