With the emergence of unlimited phone and data plans from the carriers recently, it would be a task to compare the cost and features of each carrier. Well, someone has done that for us. If you are even remotely considering changing carriers, read the following article: http://www.zdnet.com/article/comparing-unlimited-plans-from-t-mobile-sprint-verizon-at-t/
Of course, first, you would want to be sure you have a strong signal in your home area. Plus, if you travel around a lot, another important consideration is the carrier's coverage around the country. We have AT&T, and not only is it the most expensive carrier, the mobile hotspot can only be used for the device itself -- another device cannot connect to the hotspot. That would be a major issue for us if we did not already have unlimited data plans for our devices.