There are a few problems with the MiFi device...
1. It is not designed in any way to be used while moving in a vehicle... and if you try to stream pandora or watch a you tube video ... good luck.
2. The cost for the MiFi device is nominal once you realize that your monthly bill will actually be more like $60-$100 ... not cool
3.It only stays charged for 4 hours and you cannot use it while it's charging
The autonet device is cheaper, and actually has technology designed specifically for the device being in motion. There is a reason that the Autonet device is the only auto industry certified and the MiFi is not.
Check out this CNET review below.