It's hard to beat the environment at a Badger football game! I've always had a good experience with friendly fans and a fun, positive setting. There are plenty of bars and beer tents surrounding the venue, so the party goes on well before and after the event.
My biggest beef is about Camp Randall is the difficulty in parking. Sure, you can pop a good $20 to some homeowner to park in their yard. I'm not content with that. If you're fine with walking, you can find free street parking down toward the zoo - the earlier the better. Often you can find a free spot right next to someone charging $15 for parking in their yard.