I had a pair of HMK Pro Boa's for about two rides last year, and sent them back. They were extremely warm but didn't seem to breath very well. This resulted in my feet being soaking wet from a combination of sweat and just being in the deep stuff. My feet were still warm, but the issue I had was, what if I have to spend the night out in sub-zero weather with wet feet...no good.
I have to agree with Skocz, I've had HMK's for a couple years now and I have wet feet every day, sometimes just damp, sometimes I have water squishing between my toes. Most days it's just a bit of an annoyance, my feet are still warm but wet, but if I ever had to spend the night it would be a big problem even with the extra socks and plastic bags I carry in my pack. I've been thinking about getting Klim adrenalins for a year now but I really don't like the fact that you can't take the liners out to dry. I ride with guys that have them and although they say they love them their feet still get damp from sweat. And nobody seems to have anything good to say about the Radiums, even the people selling them.