Just Installed my H50 2day and its Amazing, much better and quieter than any air cooler. Even if a big cooler can keep it the same temps this thing is soo much smaller than any heat sink setup. totally worth it.
Couple of pointers tho, it wont fit in a case where there is a bar going across under the PSU. I changed the arrangements around on mine, put the radiator onto the case and I used the the long screws and threaded them through my Bequiet fan that has rubber non screw mounts and it worked a treat. havnt had time to test heat yet but it seems decent, but I would put own thermal paste on instead of the the prepasted stuff, going to change that at the weekend.