AT&T 3G and 4G are very similar. Where it gets exciting with AT&T is 4G LTE. LTE is a totally different technology and faster than most cable and DSL systems. If you're happy with 3G on AT&T you won't find 4G all that much faster. It is an upgrade but fairly minimal. Here is a good article on the subject.
Living full-time in the San Francisco Bay Area
Camper: 2004 Damon Daybreak 3285 WorkHorse 8.1 Toad: 2010 Mini Cooper Clubman S - BlueOx Toy: 2012 Ninja 650 - Versa Haul VH-SPORT-RO
I have verizon and only in the very large cities do they have 4g. When we were in Long Beach we got very fast speeds. Near 25 megabit. But in Tampa is was only in the 9 megabit range. But still much faster than 3g in the smaller cities.
Easy enough to check the Verizonwireless.com 4G coverage map and you will quickly find that it is only in MAJOR US cities. There are entire states without any 4G service at all and along the interstate highways there is no 4G service from Verizon. AT&T has the wost coverage 3G or 4G with the exception of T-mobile of any carrier.
In California, Arizona, and New Mexico we get on average 150K speeds with Verizon using the available 3G service. For connectivity while traveling we get by with Verizon but also stop in at libraries in towns to make use of their WiFi service.
We have found it a lot easier to get good internet connectivity for free traveling around Costa Rica then for pay when traveling around the USA the situation here is actually getting worse with Verizon and AT&T abandoning DSL. They make a lot more money off wireless $10 per gigabyte overage fees.
We only get AT&T's E here. I'd love to see a single G.
I feel for you, we just got 3G last November. The sad part was the tower is only 3 years old and they didn't put 3G when they built it. Wondering why when they didn't put 4g instead. Like another poster said they just don't care about the rural folks. But neither does cable and telephone companies. We are always left behind.
But with that said, since we travel a lot, I would get 4g capable equipment. But I don't usually upgrade annually.