After playing with mine for a few days, I'm very impressed.
The most noticeable issue is how well it tolerates higher temperature.
From what I've seen, this device does not really require any secondary cooling unless you are in 90+ F temps. Even at higher temps, there is no drop in hash rate. It's been a particularly hot few days here.
I've run it in a room with the window open and no additional cooling.
At 73 degrees F ambient it runs at 62 degrees C pushing 60.235 GH/s.
At 83 degrees F ambient it runs at 67 degrees C pushing 60.188 Gh/s.
I had it up in running a few minutes after the box was open and it's been running for days without a hitch. I haven't plugged in the killawatt yet, but it's running off an 850w PSU that is already powering a 7950 and 2x 6870s.