Do some tests in different areas, you might find the problem's limited to a specific spot rather than everywhere. I get bad speeds at my work, sometimes around 300 kbps at max, but often around 30 kbps. I thought my slow 3G speeds might be the phone or some electronic interference, or just Sprint's overall 3G service. But I found that just a mile away, I got speeds around 2000 kbps (it was actually faster than some crap free wifi I tried to use).
So I found that Sprint has decent 3G in my area, just not consistent, and not where I need it most. Unfortunately, just knowing that doesn't really help that much. It doesn't seem like Sprint really does anything for dead zones, even in large metro areas.