Here's a good brain teaser for you mates:
Two identical SDXC cards (Lexar Pro 128GB, R:150mb/s W:~43mb/s) produce drastically different results: one boots ML fine, while the other, even without ML loaded, will temporarily "brick" my T5i/700D. This "brickatose" state can be broken by quickly ejecting the battery, but if the bricking card is in the slot—no matter what data or lack of data it has—the camera will remain dead.
The only other difference between the two cards is one is painted red and the other blue. Red likes to play. Blue likes to kill.
It only seems related to ML because before I loaded ML onto Red, both cards worked fine. Something must have happened between then and now to make Blue the Cam Killer.