My cousin have tested it and Exhaust as more benefits, the CPU would run a little hotter (5-6C more for a 3770k at 4.6ghz 1.3V) but the GPU will still exhaust hot air and in is testing, the GPU temps raise by about 15C as hot air was now trapped in the case and can't exhaust by the front exhaust (he reversed the air flow totally and that don't work at all, heat still raise)
FYI: he's using an Obsidian 650D with Noctua NF-F12 fans everywhere with an H100 (not I)
Yeah but some people will say I will use some heated air to cool the rad, but on second thought I have the corsair air 540, awesome air flow so I'm not sure what to do...,..
I've tried many push/pull configurations before, and exhaust has always worked well for me. I'd rather exhaust the hot air from the graphics card than the processor as it is more heat significant inside the case than a processor.
Allow cold air to enter through the front, cool the graphics card, rise, and then exit through the H100i.