A little additional. Yesterday we were just south of Charlotte, NC where one would expect good Verizon coverage. We had full bars but no 3G and tried to use Maps. Just wouldn't work. As soon as we drove north further into the city and picked up 3G Maps for directions just loaded quickly and even popped up 'current location' accurately as we drove. So, it seems to me that 3G covereage is needed for some if not most decent use with the Ipad and a moble hotspot on Verizon but wonder about Mifi still.
AT&T has long let customers from home internet and wireless data piggyback on their wi-fi service. More options are always nice, though.
And things will get more expensive as tiered pricing becomes the norm. Much more expensive.
Posted from my iPad WiFi 64GB
iPad mini 16GB wifi White & Silver I iPhone 5 Verizon 16GB White & Silver I iPhone 4 Verizon 16GB Black (Retired to iPod like activities) I Late 2011 MacBook Air 13"