M Huston
I have two of these that I am using with a GoPro HERO3 and they work great (I will be getting more!).  While I could do the 64GB, I (so far) am preferring the 32GB, because the card is about full right when a battery reaches the end of it's life so I can swap a card and battery at the same time and save opening/closing the case and swapping parts all of the time.  The card is plenty fast, never had any hiccups with that and they have proven to be quite reliable as I have a 3rd card that I have been using in multiple mobile phones (HTC and BB) since 2010 and have never had any problem at all with any of them.