I just did a PRL update as I have been doing several times a day for the last few days, and wouldn't you know it, my PRL just reverted "BACK" to 21081 and I have my 3G back! My phone was on 50580. Using the "Netmonitor" app it now shows I am on the EvDo rev.A network again. Just ran a speed test and I went from the crappy speed of only .13Mbps download to now getting 1.19Mbps. I can only guess Sprint has been reading about this problem here on Android Central