My quick thoughts on the bands I saw:
Job For A Cowboy - 3/10. Not my thing.
Emmure - 1/10. First time seeing them...NOW I get why nobody likes them!!
Machine Head - 7/10. Really good performance. They seemed to actually be enjoying being there.
Children Of Bodom - 5/10. Didn't really care for them, maybe because the heat was starting to get to me. Cut it short and headed to the pavillion.
Amon Amarth - 8/10. I wasn't familiar with their material, but I thought they put on a good set.
Mastodon - 6.5/10. I was really looking forward to seeing them, and was a little disappointed. To me, they just looked like they wished they were somewhere else.
5FDP - 8/10. I don't get the hate for them. I always enjoy their live shows.
Rob Zombie - 9/10. Always a good performance from RZ! John 5 seemed to be interacting with the crowd more than past shows.