The new service plans for the iPad shows a bit of Apple's influence. The plans are 1GB for $20, 3GB for $35, and 5GB for $50. As I understand it, they are no contract prices. You pay $130 for the mifi and then the service plans as you need them. Without a contract, the mifi costs $260 for non-iPad users and the 5GB service plan is $10 more per month.
If you like Verizon and are a heavy user, this will be good news because the 5GB plan is cheaper per GB than the $25 AT&T plan. However, if you are like me and have decent AT&T service and the unlimited plan, it would not be worthwhile. Or if you only use 1-2 GB monthly, the AT%T plan is cheaper. One advantage of the mifi is the ability to use with other devices, like an iPod Touch or laptop. Bad is the short battery life of the mifi unit.