I have a GoPro and am really impressed so far. As Twoshot said the batteries aren't awesome (I get two and a half hours out of each one) but I have two as they're like $35.
There are endless mounting options and they come with a waterproof housing.
I have a suction cup mount for my 4x4 and I have a head strap mount for hunting (only used it at night so far for possums so I can't really comment on how it'd work for that).
I'd recommend them to anyone if that's the kind of camera you're after.
Here's a couple of my test vids so you can check out the quality (make sure you hit 1080p).
You can see for bunny shooting etc you probably wouldn't be able to see them at any distance. Ducks would be even further away.
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