I use SuperShuttle whenever I travel. The drivers are always polite and helpful, the staff at the airport are always polite and helpful too. They make sure to give me the ETA and the number of the van I am waiting for. It is so easy to book online and then to find them at the airport. I like the text messages that tell me how far out the driver is-it's like someone reminding me to finish up and be ready (I tend to wait till the last minute).