I use an H50 with an i5 (Cooler running clock-for-clock I believe) and on the stock fan the H50 was only really good for 3.8Ghz tops before the temperatures were getting where I'd rather they didn't. Now with two 1900rpm scythe slipstreams I can get 4.0Ghz stable over masses of linpack but there are still better coolers out there.
Am liking the look of this, I'm tempted to get one
So yes, the H50 is excellent... if you want to buy mine
What's annoying is that my i5 does 4.4Ghz at 1.465 volts, but the H50 won't keep it cool at those clocks - so my only choices for maintaining that under stress would probably be custom water, the old northQ version of the H50 with the double rad, or that noctua.