I recently borrowed a thermal camera to figure out how hot the board gets, especially when powered from the higher end of the expected supply voltage range.

This is an image of the board taken with a thermal imaging camera. The shot was taken after feeding the board with a 10V supply for an hour or so. The LDO—where the voltage is dropped to 3.3V—obviously shows up as hottest, peaking at about 74°C. Supply current is around 80 mA here, meaning that the LDO and the diode before it have to dump about half a Watt into the air and board.

The conclusion is that it's wise to feed the board with a lower voltage to keep losses down. No surprises there :-)