back when I was buying my gopro stuff (Oct '13), there were all sorts of problems with Sandisk's high end cards. They were labeled as Class 10, but when actually tested, they did not meet the Class 10 specifications (or even come close), so I avoided them. Don't know if they cleaned up their act or not. I know at one point, GoPro yanked Sandisk from their approved list on their website because their cards were crap. Straight up false advertising if you ask me.