It was great experience. Everyone loves it.
Car was old and damaged on top due to weather.
The tour pick-up points was so confusing as not a single sign is posted and calling the local agent was no help at all. The total tour hours over-all doesn't give you enough time to do the Hop-on/Hop-off.
Our guide was very interesting. The tour included many landmarks in downtown Houston and around the Medical Center and Rice University. I plan to go on the same tour again.