Hi Judy, I can only speak about Verizon. We use a Verizon air card when we travel. One great benefit is if you are using a laptop you can search the internet while driving down the hi way at 60 mph. It does come in handy when you are trying to find places or phone numbers in strange towns or reading the moc while driving
The reception is that of the phone maybe slightly better. Usually if you have a phone signal you will definitely get a signal on the air card. I wish I could say it has worked everywhere we have gone, there are a few places the signal just didn't come in. As far as networking two computers I dint think you can but, we haven't tried and that might be something to ask Verizon about.
Rick & Sharon