I would not use a go pro for paintball, would lean towards the Contour range myself, possibly the cheaper roam version, and they make mounts specific now i think for paint balling...
The Contour is better suited (in my opinion!)
Current models are the Roam2 and +2
Contour did to down a short while ago and close their factory, but have come back
The +2 is the 'top of the range' but the 'Roam2' has identical specifications for the items that realy matter
The differences come in with the +2 having Bluetooth (change settings and view the recording from a smartphone), a removable battery (swap to a spare for more life*)
Both have the rotatable lens, so you can make sure it is the right way up no matter how it is mounted
The roam2 is waterproof in itself (1m) the +2 is not
But both can take paintball impact without a case
Unless you want the extra features to switch settings on the fly, or to view what you are recording / have recorded (bearing in mind these will use up your battery (so you would need a spare) but these are definately useful if you are making a film as opposed to filming your activity
* with battery life I can have the Roam2 last all day if I'm switching on/off, or for a morning or an afternoon if on most of the time. I also use usb battery packs which let me recharge the camera as well as my phone etc
The point about special mounts can be a red herring. This is a big selling point of the GoPro, but with the contour having a standard screw socket in the base it opens up almost every single camera mount in the world. You have both the contour rail system and the standard camera system
Buying the branded mounts is an option, but best results are to be had by thinking beyond the manufacturers catalogue
For head mounts, such as the side of your goggles the contour system is ideal
For barrels companies are getting on the bandwagon with paintball specific barrels, but this is the staple diet of action cameras. Handle bar and roll bar mounts have been around pretty much forever