A colleague has SPRINT for his personal phone and while having lunch in the Galleria he had 4G LTE for a few minutes before we went inside for lunch.
I had him download the Speed Test application and it was averaging about 20Mbps down and 6Mbps up.
For any wireless network that is good IMHO, no it is not the 50Mbps I saw on at&t Mobility nor the 35Mbps on VZW, but for SPRINT which is more of a value provider I should think that 20Mbps is good (about equal to Cable i-net).