19,99 are worthwhile :)

After six months use and an estimated 50 charges I could not detect any loss of performance - Original Original remains halt.
Depending on the temperature (in operation from -10 ° C to + 40 ° C) can I get between 90 and 120 minutes of full HD at 30fps. (The values ​​refer to GoPro Hero2)

At least a spare battery can only recommend any GoPro owner;