Vonlane is starting Dallas/Houston service on April 20th. I have been watching with much interest the progress of this luxury bus service since they started last May between Dallas and Austin.
The terminal in Houston is the Sheraton hotel on the north side, near the Bush Airport. At first glance, it seems to me this is way too far from downtown. However, on second thought, it might make sense. This is slightly over a 3 hour trip, similar to Austin. The car rental locations are directly across the street. The full trip into downtown Houston would take at best 4 to 4 1/2 hours or even more to Hobby Airport on the south side. They are competing with Southwest Airlines and/or American. A trip of more than 3 hours would not be competitive.
They claim the demand for this service has been huge. We'll see what happens.