Terminal A is pretty miserable. No TSA PreCheck line. You have to go to Term C for that. No Delta Lounge. You have to use the KLM Lounge in Term D. But the tram gets you to/from terminals quickly.
1 hour of free wireless access for some AMEX cards, but 45 mins free for everyone. Click on the "complimentary" wireless link lower down on the page and follow the directions.
I am ashamed about the long kilometrique queue at the passport control. Prepare yourself to wait minimum 1,5 hours (overpassing not honestly the other people) before to catch your connecting flight.
If you have a long layover after midnight— make the way to Terminal E. Every other terminal isn't worth attempting to sleep for your layover. I've tried.
Get the breakfast tacos or burrito at panchitos in terminal B. Ask for it fiesta style and they'll throw on sauteed peppers and onions, no extra charge!
Access to A gates on both sides of the terminal! Don't go to the wrong security line! If you do, there is a walkway to the other side past security though!
Travel a lot and deal with "normal" air travel problems often but I will avoid IAH always (awful layout, long lines for help, of course humid and, though friendly and caring, no REAL help given).
George Bush Intercontinental Airport is the 8th busiest airport in the U.S. and offers service to more Mexican destinations than any other airport in the nation.