Cons: Case limitations, mildly complex installation vs air coolers
My temps dropped by 10-12C compared to my Noctua. WOW. Never expected such a huge improvement from the switch. I believe much of the improvement is that the H110's radiator is further removed from my graphics cards, and as such my CPU temps are affected less from the GPU waste heat.
I am using this cooler with a couple modifications. First, I am using a pair of Noctua NF-A14 fans, since I already had them in the roof of my Storm Trooper and since they are almost certainly superior fans to the stock Corsair offerings. I also replaced the thermal compound that shipped with this with Noctua NT-H1, since that's been the best performing thermal paste in my experience. I also use the fans as exhaust (rather than Corsair's recommended intake), and have them on a fan controller.
With all that, I am able to run my 2600k at 1.41v (4.8 GHz) and my gaming temps in BF3/4 multiplayer stay below 70C. Prime95 load temps stay below 80C. That's seriously impressive!
The only cons to this cooler are case limitations due to its size, and the minimalist instruction manual makes installation a slightly slower process than it needs to be.
My relevant specs:
ASRock z68 extreme7 gen3
i7-2600k @ 4.8 GHz (1.41V)
16GB ddr3-2133 c11
EVGA ACX 780 SLI
Storm Trooper case