Easily my favorite food joint on campus. It may not be 'real' Mexican food, but it certainly is delicious. The downside to that, is that there is always a line, but the staff is usually very efficient and courteous.
It's hard to find a combination that is bad, but I definitely suggest more people try the fajita vegetables. It's a completely different flavor than a standard beans, much sweeter, but definitely delicious.
Watch out for the Guac though; it's good but they charge you for it.