I've been spray tanned stacks of times, in those booths and by someone actually spraying me. I also do spraying tanning myself at work. It gives a really good even colour and generally no streaking. Just make sure you keep your fingers seperated when you get it done, otherwise your hands are brown but the skin between the fingers is white!
Like the other girls said, make sure you exfoliate before hand, and make sure not to have any moisturiser or deodorant on, on the day you are getting the tan, otherwise the tan won't apply properly. Also, wear loose dark clothing afterwoods, you won't be able to shower for 24 hours, or til the next day, the tan still develops after you have it done.
Spray tans can look a bit icky and uneven the day you get it, but once you have showered the next day it looks perfect.