Just got a few of these, appear to be running well (thanks to Kano's idiot-proof setup instructions!) Dumb question number one - how do you know if they're overheating? I've rigged up a fan as a test, but it's probably not ideal...
If you can stand touching the heatsink for more than several seconds then temp is fine.
The fingers I burned more during soldering can stand more heat than the others, for instance. Would definitely be helpful to have some kind of number to check for with a thermometer. On the other hand, I guess they throttle themselves anyway if they overheat.