Since my favorite college team is in the Big12 (WVU), and the Big12 has a deal with FS1, I prefer FS1. Although, in recent months, FS1 really pissed me off when they fired Jay Onrait and Dan O'Toole. Those guys were effin' hilarious! Sadly, FS1 had no idea how to promote or use them. Thankfully, Jay and Dan are going back to TSN in Canada where they were appreciated so much more.
ESPN has soured on me because of all the political crap, as well as the fact that most of their talking heads (save Scott Van Pelt) have terrible personalities. Unless it's a live game where WVU is playing, I very rarely watch ESPN.
FS1 seems to be a bit more tolerable than ESPN at this point.