I think it just reconnects you to the nearest tower.. I think it works on every sprint phone.. I remember my treo could do this also.

My guess on the data issue is a conflict that the EVDO and the voice radio, I know the treo had somewhat of a conflict that you could only do voice and no data or data and no voice, which is true of EVDO Rev 0 phones but I think the blackberry is trying to overcome this software wise and something is getting messed up. Thats just my theory.