The trouble with the map is that it is too high level and makes it look like their is a lot 4G LTE in certain areas. I live in the Detroit area and I use Sensorly. However, I rarely get 4G LTE. And when I do, it is not usually very fast. What I do notice is that 4G LTE goes in and out on a daily basis and from block to block. For example, there is a restaurant I go to and I get 4G LTE their about 50% of the time. The other 50% I only get 3G. Another example, I never get 4G near my house, but Sensorly shows it up and down my block. In addition, Sprint has not even announced Detroit Metropolitan area yet. So, what I suspect is happening is they are testing and turning on and off 4G at different locations. I did notice the reception at my house became really bad for about 1 week and then recovered. Of course this could just be my phone. I have a Sprint HTC EVO 4G LTE.
David