Alamo is so convenient for me and the best prices around. When I go, I try to go early because they back up pretty quickly.
There is a nice shaded outdoor waiting area and seating inside that offers complimentary fountain drinks and water. You can feed the massage chair some ones and get a little rundown while you wait.
I've never left unsatisfied! They are friendly and move as quickly as they can while still doing a good job. The ONLY thing that has ever bothered me while I was there- the restrooms were out of order (not a big deal, the AMPM 20 feet away has some) and the girl behind the counter told me they have to clock out to use it. Not sure what the logic is with that but it seems like a pretty unfair practice.
Overall, it's the only place I go for a car wash and detail and don't plan on going anywhere else.