The main feature you have to keep in mind is that a GoPro has an extremely wide lens. This means anything over 15 yards away typically looks like an ant. Also, you're most likely using the waterproof housing anytime you're out in the woods, so that means no sound.
Aside from that, my biggest suggestion is that if you get one, seriously consider getting a remote for it. Once you set it up, you don't want to keep fidgeting with it just to turn it on when an animal comes in. A 16GB SD card will only hold about 2 hours of video, so you can't really just let it run, and it's really inconvenient to have to mess with the angle/turning it on every time you're getting ready for a shot and wondering if you're settings are right while it's on your head mount.
Overall they're great little camera's for supplemental angles. Clear footage, super durable, but without some of those other accessories like the remote, you're not going to get all you can out of them for outdoor usage.