I've never had any problems with my phone that Sprint wasn't able to fix.
I was in here the other day and got my phone upgraded. Due to the high volume of people waiting in line, it took me awhile to get it, but I think if people stopping coming in here to ask stupid questions, the lines would be shorter and faster.
By the way, the Galaxy S4 is the shizz and if you're wondering what phone to get next, that one is where it's at. It plays "Fruit Ninja" perfectly.
Most of their phones are really nice and work well. Except for EVO. That thing is a piece of crap.