Sprint is planning to continue offering unlimited data on future iPhones, even for an LTE model. It definitely introduces a new dimension to the carrier decision for my next phone. The last time I bought an iPhone was the summer of 2010, when Apple released the iPhone 4. At the time, AT&T was still the sole US carrier for the iPhone, so there were no plans to consider. (Fortunately, I was able to grandfather in my unlimited data plan.) The choice of plan takes on added weight with the addition of LTE. People with LTE-equipped iPads are finding that since LTE is fast enough to do things like stream video, they're going through their data plans very quickly. Assuming that the next iPhone has LTE and AT&T doesn't allow me to keep my unlimited plan for LTE, I'll need to pick a new plan. As of right now, the iPhone is available in the US on AT&T, Verizon, and Sprint, and each has its ups and downs when it comes to data plans.
- AT&T: There's a certain "devil you know beats the devil you don't" factor at work here. Unlike a lot of people, I've been generally satisfied with my AT&T service. I spent most of my time in large cities, and the only places I've had trouble are in very rural areas (western Iowa) or buildings that tend to block cell signals. Still, AT&T doesn't offer anything that sets it apart from the other carriers. If I stay on AT&T, it'll probably because I didn't have a compelling reason to leave and not because of something inherently appealing about AT&T's service.
- Verizon: Verizon gets a lot of press about having the "best" network, and I'm sure at least some of it is deserved. Anecdotally, my friends who have Verizon iPhones seem to get faster data throughput on 3G than I do on my AT&T model, but it's not a very big sample size. To me, the most appealing thing about Verizon is that they seem to be building out their LTE network faster than AT&T. My guess is that for the next year or two, LTE will be available in more locations on Verizon than on AT&T or Sprint. Then again, I tend to spend most of my time in cities that already have LTE, so geographical coverage may not be that big a deal.
- Sprint: The newest iPhone carrier in the US, Sprint has differentiated itself by offering unlimited data after the other carriers stopped. Today's announcement that they'll continue to offer an unlimited plan with LTE is certainly enticing, although they haven't indicated what the pricing might be. I can imagine Sprint charging more for unlimited LTE data than they do for 3G. Coverage is also a question with Sprint, as they generally cover a smaller geographical area than the other carriers. Nonetheless, unlimited data could be just enough to get me to give Sprint a try.
Obviously, we'll know more whenever the next iPhone is announced. (Looks like it'll be in the fall.) Chances are, all the carriers will tweak their current plans for an LTE iPhone, but it's very unlikely that AT&T or Verizon would start offering an unlimited plan again.