It's been a couple-few years, so my opinion may not be very relevant anymore, but I had a poor experience with T-mobile/Sprint on both networks. Signal was too weak to even make calls in a number of locations. I feel like out of the two when I had both around the same time, the Sprint network was worse, but that network is basically gone at this point post-merger. It did improve quite a bit leading up to the shutdown though in terms of coverage, but still a bit slow. T-mobile still has 2G up and running apparently for another year, I guess to fill in the gaps.