I had no idea such a thing even existed in Phoenix until the nice chatty lady on the plane suggested it to me. Thanks, Valley Metro Rail and nice chatty lady, for making my 5 hour layover in Phoenix way more fun than the free wifi at the airport could possibly ever have, and helping me fall just that much more in love with the gorgeous state of Arizona!
As I understand it, there isn't exactly a extensive public transportation network in place -- YET -- but this is a great start. It's one simple line that connects downtown Phoenix, the airport, right through downtown Tempe and Mesa.
I took it from the airport to Tempe to walk around for the afternoon, grab dinner, window shop, enjoy the sun, generally be outside and happy and looking at cactii and non-flat terrain and SUNSHINE and not being in the airport! I'm such a fangirl!
It's clean, quick, well marked and easy to navigate, and if you were starting from scratch on public transportation infrastructure, I don't know if there are many more logical routes to begin with.
I can see how it would get a lot of traffic with university students, people working downtown, and my favourite, visitors in town for events at the convention centre downtown. Being able to offer an non-taxi, not rent a car option for visitors is SUCH a plus for the city, and just makes so much sense - I love it! Go Phoenix!