I have straight talk and a dumb flip phone, works for me, 35.00/month. My GF has a smart phone and straight talk and she likes it well enough. The only drawback was the cost of the phone, 600.00, but the service is 45.00/month with no contract. As I understand it they use the same towers as Verizon, not sure if that is correct.
I can tell you for fact that either there are glitches in their system or coverage is not the same. I got a friend that put his whole family on it and they have issues.