This is the huge event center owned by the University of Texas. All the basketball games and indoor sports are great to watch there, but concerts and special events can be pretty hectic. Parking is an absolute nightmare. There is no where to park and the biggest lot is across the highway. It is at one of the busiest intersections in town, so large groups can stop traffic and back it up even more. This place has tons of seating and is usually very well staffed, so that's always nice. Just go early so you can find a decent place to park (or take cash to pay).
I've been to several events at the Erwin Center and I must say that it is best suited for sporting events. Concerts are terrible there, but the sound kind of bounces around the venue. I have been in worse concert venues though.