Verizon is still slightly ahead of T-Mobile when it comes down to LTE network reliability, while AT&T fell down to third place now. On the LTE speeds front, the two network performers swap places, and T-Mobile scores a tad quicker download speeds than Verizon on average. When it comes to 3G speeds, however, T-Mobile beats by a mile, both in speed and in latency, so even if you aren't covered by its LTE network, there would still be nice speeds to fall back on.
Sprint excelled in only one category, as it has the lowest 4G latency of them all, but it's AT&T that showed the most mediocre results, not earning a star in any of the supplied metrics. When it comes to actual coverage, that's a different story, but as for quality of the big four networks, T-Mobile and Verizon take the cake again.