They won't be waterproof. The battery life is probably exaggerated, possibly by a lot. You'll probably have to jury-rig some kind of mount, they won't generally have suitable mounts for bikes. They're likely to be significantly less shock resistant - whether that means that they break in a crash, or they break just hitting potholes.

Don't discount "Chinese GoPro clones" - I have an SVR200 and I actually think it's a better camera than the GoPro Hero3 White that it replaced. Better in several ways, and not worse in any way. Also $80 cheaper.