I bought a Mobley as a backup to my Verizon Jetpack (20GB/ month for $100.07 converted from the old Millenicom plan). I still find that in rural areas the Verizon network generally is more likely to find a tower.
One interesting discovery. Under weak signal strengths (over -100dBm), while the Mobley often shows faster speeds using a speedtest app, it seems to drop out more often than the Verizon jetpack when listening to internet radio.
In any case, it has been useful for those rare occasions where the only towers are AT&T's. At $22.05 per month, it is well worth having since I spend lots of time on the road.
