I'm yet to test if it is compatible with a GoPro because mine hasn't arrived yet (gotta stop using ebay!!!). Speed wise I'm sure it'll be fine but it isn't quite the claimed class 10!! Not bad for the price I guess......
Max write speed = 9.05MB/s
Min write speed 7.10 MB/s
(it was about 7.50 for most of it)
Read Speed fixed at 14.20 MB/s
It could possibly be the laptop SD slot that I'm testing it in but I tested it in my desktop using a USB SD reader and it was even slower than the above.
I think the moral of this story is that if you want you memory card to perform as it is meant to, steer clear of ebay. If you're not too fussed about speed then it is spot on for the price.
EDIT:
Tested on another laptop (top of the range) and it peaked write at 10.2 MB/s and a minimum of 8.0MB/s... better but still not what it's meant to be.