The fractal Arc midi takes a H100 . As my own rig testifies.
Good kit the H100 . My i5 2500k O/C'd @ 4400 is yet to see a temp higher than 32 degrees. Case is excellent too.
Still don't see the need to spend so much money on a cooler like this. For less than 1/4 of the price coolers like the Hyper 212/EVO or even my own Arctic Freezer 13 can keep an i5-2500k cool at over-clocks of 4.6GHz+
All that extra money saved could be better put towards the next best GPU or an SSD
Also aesthetics come into play. You can hide the radiator in the top (depending on your case). Watercooling can possibly look very nice and clean and that is important for a lot of people. Otherwise there wouldn't be cases with windowed side panels.