Wait until they start flying Spirit*.
Discount Airline Spirit will serve IAH, Chron.com
Non-reclining seats, fees for carry-on baggage , disastrous customer service and fares that may not be as cheap as advertised coupled with a Houston passenger base that has high expectations for even discounted coach product (if you don't believe me, read the comments of almost any UA article on Chron.com, or spend some time at IAH.) is a recipe for disaster.
And, believe me, some Houstonians hold a grudge. (again, go take a look at the comments for the Spirit article, it's a river of fire against UA for "abandoning" Houston.)
This could be the best thing that happens to United. Compared to this airline, UA economy is going to feel like first class.
*this is not necessarily a knock on Spirit. If you know what you're getting into with them and are OK paying fees for everything but oxygen they're you're airline, and some people really believe (as they do with Southwest) that they are getting a deal on the flights.