The H100i is definitely going to be better for overclocking. Water cooling will almost always beat air cooling, unless you get a Noctua NH-D14. I hate the stock fans that come with the H100i. I picked up a pair of Corsair SP120's for my H100i and they work very well. I have my 8350 at 4.8Ghz 1.52 volts. Your CPU might be a better overclocker, or it might be worse. Just hope that you get a nice binned chip.
@MikeYFItalian: Just want to correct you on one thing for the benefit of OP who will be reading your post. H100i is a liquid cooler for the CPU. A real water cooling setup done right will beat air cooling, including the Noctua NH-D14. The Noctua NH-D14 is a high-end CPU air cooler and can compete against H100i almost evenly. But that is a far cry from saying it can stand up against a water-cooled build.