This is a superb bike helmet, the best I have ever worn. I've been wearing the size small for two months now and have put about 700 miles on it.
In those 700 miles, I haven't had a single drop of sweat make it past the brow of the helmet and down to my eyes, and I sweat like a nun in a whorehouse. I think this must have to do with the airflow but maybe it's the fit of the helmet on my forehead. My hair gets wet with sweat, but no extra drops make it out of the helmet. The airflow is just outstanding. I do have a theoretical worry about a bee getting turbo blasted into my scalp but so far this hasn't happened.
I've worn this thing for as long as 6 hours without headaches and I wasn't dying to take it off. The helmet is light and doesn't block my field of view.
My only nitpick is that the buckles that hold the strap together just below your ear is a bit flimsy and sometimes the camming part of the buckle pops off if you are making an adjustment. If you dial in this adjustment at home then you don't have to worry about it.
This helmet might favor those with a roundish head. My head mostly makes contact in the front and back and less so on the sides, so if you have a more oval head it may not feel so secure on your noggin.
I have the 2011 version but I don't see any difference in the 2012 except for that it comes with a cocoon to protect your "investment".