You should check the map supplied on the Sprint site. It will give you a much finer look at the coverage within that green area. I had it for about a week. It worked extremely well at work in the Uptown area. Coverage is pretty strong there, even in buildings. On the west side of the metro, it was extremely spotty. I'd have decent coverage here, but 1-2 blocks away would have zero coverage, even within the green space. The week I signed up we had a lot of rain, and being that the edge of coverage, it became pretty weak, or useless.
That said, just be aware of the real coverage. When it was working, I found it to be very fast and quite reliable (within that connected space). I was able to stream RT video driving my car to a buddy over Skype and he said he was getting 15-18fps reliably from me, with no audio delay. Not bad for mobile. Then it would just disconnect. I dropped it, will be waiting until I could rely on it a bit more.