I'm guessing they're are many others in my shoes.
I had sprint for about 6 years. They were good and they were the cheapest, would roam in Verizon towers without any problem.
But they just kept promising faster and faster next month, next month, next month, etc. For the past 6 years. Coverage kept getting worse and then I couldn't even roam on Verizon.
If you're out of city limits, coverage is horrible and 3g is unusable. In fact it's barely usable with good signal.
When they went to the whole "framily" plan about a year ago, they wouldn't let me switch to it because it was for new customers only. That was the last straw for me and we switched to Verizon, don't regret it.