It was the best football experience of my life. I wore blue, cheered for BYU and had a blast while the other 3 people in my group cheered for the Utes (I returned the favor the following year and got them seats in the BYU student section. The fans around me were generally good sports. They asked questions about our players and I asked questions about theirs. I learned a lot about Ute football that game, which made it all the better experience. There were a couple annoying fans that were giving me a hard time, but the BYU fans in Provo did the same thing to my Ute friends.
I say go for it!