Sprint will be upgrading a ton through this year and next year. Everyone claims that Sprint sucks but that is mostly people who live in poor coverage areas. Obviously if you live in a poor coverage area for a given provider it is going to "Suck" for you. The other thing is that Sprint uses Verizon towers when roaming. This is not limited to 3G service and is unlimited roaming nation wide on the SERO plan (Not sure about regular plans). So in essence if you are roaming and not getting Sprint service you can jump on Verizons 4G for free.
I am on Verizon right now and even with my 20% discount they are outrageous.