My recommendation would be to go with a reputable company to do the termite work. My dad works for Presto-X-Company (click on the name for website) and I know that they are in Oklahoma as well. They use a termite system called Sentricon by Dow Agro. They have had excellent results with that system and I would highly recommend the system. If you go to their website click on their logo to enter then click on the Oklahoma City link to go to the Oklahoma branch office. Tell them that Tom from the Sioux City office sent you.
You don't see the advertisements for Presto-X since they don't advertise. Most of their business is made up of commercial clients and food plants. They are an extremely reputable company though.