I went with Virgin Mobile originally because I did not want to be locked into any contracts. That is what I still love about it. You never have to worry if you decide you want to switch carriers, or if you simply don't want to have cell phone service for a while. You can go on a pay as you go or various other plans. Right now I have the 100 anytime minutes for $14.99 a month. It works really well for me. I know many other people that have the service also and they really like it.
You go online to do your account or can access it from your phone. Their differnet phones vary in price and have all kinds of great functions. They are also adding more and more features and one in the works is allowing the gps functions to work on phones. I love being with Virgin Mobile and until another carrier offers as much as they do I won't be switching. Why switch when they have everything that you need.