I own two GoPro Hero2's and bring them everywhere with me. I manage a YouTube channel for my urbex adventures and love the versatility and quality of the footage. Yes, they are grainy in low light, but bring a high power flashlight with you and you're fine. =) You more likely than not are not trying to shoot Hollywood footage so a little grain is fine for memories and to show to friends. I sometimes wear one on a head mount which makes taking photos easy. Otherwise put one on a pole and use it like a regular camcorder. I'll attach a couple links to footage I've shot on my GoPros. Hope that helps!
Titan Missile Base(pitch black and lit with flashights):
https://www.youtub...atch?v=f3-kk5z_Zss Glory Hole Mine:
https://www.youtub...atch?v=QhDor20MSz4 Atlas D Missile Base:
https://www.youtub...atch?v=O4b2wvZzNZ8