We've been using a number of Go Pros for high risk work - getting run over on start lines - going in water and so forth. They are good, cheap and acceptable for broadcast IF it's understood that this is a cam in a high risk environment. Like onboard cameras on race cars are always quite poor quality compared to the big tower mounted cams at the track.
A couple of things to note
1. Almost no controls. There are two buttons and no display to tell you what they are doing.
2. It's a very wide angle lens, so you need to be very close to the action if you want it big and exciting.
3. The sound quality is not broadcast standard, and because you have to get so close, it often blows out.
4. The little case that it comes in is excellent, but not foolproof. We've lost several to actual hits from cars. Try not to get hit by a car.
5. They don't handle bright light very well. Some things overexpose to the point of having a black dot in the middle.
You can easily transcode the native files in Mpeg Streamclip or Compressor. We use Prores and have no trouble with them.