I got a 3 MiFi a few months back, then recently paid them £15 for it to be unlocked and now its working great with my Vodafone PAYG broadband sim – 2.5Mbps down/2Mbps up :).
Had to do a little fiddling to get the firmware updated so that I had access to the web control panel.
But once I had the correct APN/user/pass settings in place its working like a charm.
I also found some info on the modem and the links are here:
PS Now I am ready for the WiFi only iPad :)
PPS Maybe I should get one or more of these for JA…