Hope I'm not comming to the party too late in terms of this thread...
I too had issue with signal after moving and told Sprint I was considering leaving since I was off contract (this was about a year ago). They sent me an AirRave device at no charge (device nor service).
Had a few issues setting it up requiring calls with AirRave support; device wouldn't sync, firmware pushes, etc. They at one point claimed that my QoS was too low on my Internet Service, which prompted me calling my Cable company to have them check my signal strength to my modem etc.
In the end, the device started working (no firm reason why IMO) and it has provided full coverage throughout my townhouse. I have yet to be charged for the device (as agreed upon) and, should I be charged, will consider dropping my account. However, I doubt they would be willing to lose a loyal customer just to gain $5 more a month.
Hold onto the packing materials -- you are required to send the AirRave back (if they provide it complimentary that is) upon account termination. Otherwise, I use my phone as I do anywhere else with the same performance, only solid signal in an area that formerly had none.