Most carriers require that you sign up for a data plan when you buy a smartphone. Again, Sprint charges $10 a month for unlimited data -- that's the same fee that covers the texting.
AT&T and Verizon offer cheaper voice plans than Sprint, but they make their money back on the data side. AT&T offers a base plan of $15 per month for 200MB of data; go over, and it'll charge you $15 more for each additional 200MB. Its 2GB plan is $25 a month, slightly better than Verizon's 2GB a month for $30. However, if you regularly use more data,but aren't quite ready to shell out for the Uunlimited options, Verizon offers additional tiers at 5GB ($50 per month) and 10GB ($80 per month).
Each carrier also offers hotspot capabilities, letting you share your iPhone's cellular data connection with other devices, like an iPad or MacBook. AT&T's hotspot option requires you already subscribe to its top-tier 2GB data plan; on top of that, you'll pay another $20 per month -- though you'll also get an additional 2GB of data. Verizon charges $20 a month for 2GB of hotspot data, which can be added on to any of its data plans, and Sprint offers a $30 option.
Of course, coverage is a comparison we can't really make for you. The advantage here depends on where you live and how you use your iPhone -- and if you, for example, live in the suburbs but work in the city, it can get even more complicated.
Verizon, of course, has the broadest reach of the wireless companies in terms of people served, with 106 million subscribers; AT&T comes in second with 95.5 million customers, and Sprint brings up the rear with 51 million customers. Before deciding which carrier offers the best service, you'll want to look at their coverage maps: You can see them at Verizon's, AT&T's, and Sprint's websites.
But as we've told you before, there's no experience like real-world experience: You might want to ask your neighbors which carrier they're using, and what kind of service they get. And you might check out services like the RootMetrics app, which crowdsources the process of testing neighborhood wireless coverage to create maps of which carriers perform best, and where.
Each carrier has advantages -- both tangible and less so -- that we haven't quantified here. For example, AT&T offers rollover minutes and free access to its nationwide network of Wi-Fi hotspots. Verizon, on the other hand, has tended to score the highest in customer satisfaction among wireless carriers. Sprint, as the newcomer, has the most to prove on the iPhone front -- but that unlimited data plan may give it a leg up in the market.
Because the charges, coverage, and other qualities of each carrier varies, the iPhone operator you choose might be different from your coworker who lives 10 miles away -- and you'd both be right.