So to update as of mid-August 2013:

Except for United, all US airlines fly into the new terminal 2 (with nice jetways).

At some point this year, United moved from the horrific old T-3 to T-1. All the Mexican airlines use this terminal as well. While T-1 is not as nice as T-2, they have added a Starbucks and there is a Subway as well if you are looking for something healthy. If not there is still pizza, hot dogs and BK. Practice tip: the A/C doesn't seem to work too well here (in mid-90 August heat) so if you want to stay cool grab a table near BK rather than the main waiting area.

All arrivals are processed through the new facility in T-2. It was pretty quick if you fill out the card completely before getting to the front.