We have a GoPro and the size will not get in the way at all including its very light. Got ours a couple years ago and they have a new model now. Depending on what you do, you may want to get a head strap or chest strap. I have both but found when reeling in the beast my hands got in the way of the video of the catch. I use the head strap over my hat and not an issue at all as the camera is very compact and light weight. They also make all kinds of suction cup do-dads to attach to windshields of vehicles including airplanes. I believe even Adam Eakle's cameraman uses a GoPro to film footage. At least thats what I was told by a friend who fished the DAV fishing outing recently and had the cameraman in his boat.
Another thing is the quality in HD is fantastic hands down various setting on my camera but I'm sure better ones now. The only issue I have is the vidoe footage is in wide angle and you have to have video software to allow you to crop the background if you desire not to display backgrounds. But again the HD is outstanding and if you desire the wide angle prespective you won't be disappointed. Our camera has four different setting again 2 years old.
I would strongly recommend purchasing an extra battery or two again depending on your requirements. I leave my camera on and will hit the record button when we have a fish on...leaving camera on in standby mode draws on the battery and running battery life is like 2-4 hours in standby mode I believe and depending on weather conditions...warmer shorter cooler longer times I've found.
Next you can get various cases including water proof cases. Another strongly recommend is submering the case in water without camera in it to ensure its leak proof.
I've used ours a whole lot...my son uses it for snowboarding and loves it. Thinking I may upgrade to the new model and pass-on the other one we have now to my son.
Enjoy if you purchase...I do believe you will like-eee. But I'm partial...