I really don't understand the attraction to AIOs .... and I say this as a water cooling enthusiast. With an AIO all you are not doing anything different. The noise still comes from blowing air thru tightly spaced fins. So what will make more noise....
a) Two fans blowing air at 1200 rpm thru tightly spaced metal fins....
or
b) Two fans blowing air at 2700 rpm thru tightly spaced metal fins....
Kinda like driving with the windows pen at 40 mph versus driving at 90 mph .... what makes more noise ?
The H100 is bearable not because of anything related to the water end of things .... it simply uses slower fans at 1500 rpm..... by having 36% more radiator area (140mm x 2) than the H100i, it doesn't need to blow air at such a high speed. You could change the fans on the H100i to 1200 or 1500 rpm, but then it's performance drops precipitously.