I just upgraded from a Muziq to a Moto Renegade (V950) and the service seems to be much better. Amazing how much of a difference a phone makes. I hold calls in elevators now where my other phone would drop them. I can say I'm pretty happy right now. It was a bit of work for them to not touch my plan when I upgraded since they wanted me to move to a newer plan.
They are adding a fair amount of towers again so if coverage was an issue before check it out again. If you can get similar coverage and save a bit of money might as well. That money is better off in your pocket than in someone else's.
It has always been the case that customers who complain of dropped calls and poor coverage are the same ones sporting a 10-year-old handset and a 20-year-old plan.
Sprint doesn't need the super cheap skates. I think they have a lot to offer for the money.