The biggest LTE provider globally, Verizon Wireless, is based in the U.S., which would seem to give Verizon an edge in attracting LTE iPhone customers. But Verizon in June also implemented its with free voice and texting that is now required for new and upgrading customers. With the plan, data services can be shared over 10 devices and sold in several different monthly data tiers that subject users to an overage charge should the upper limit be exceeded.

If Verizon sells the next iPhone, as expected, the Share Everything Plan could be a deterrent to new iPhone customers, some analysts said. "Buyers have already been balking at Share Everything and iPhone 5 customers will be forced into that plan," Enderle said.

AT&T, which has also rolled out LTE service but is not as far along as Verizon in its deployment, in August that is similar to Verizon's plan, but voluntary for receiving free voice and texting with shared data plans.

AT&T also touts fast service over its HSPA +42 network that it calls 4G. The company claims its 4G network has a bigger footprint than Verizon's LTE.

Sprint, the third-largest U.S. carrier, still offers unlimited data service plans, and has shown a strong interest in attracting LTE customers with its launched July 15 and now available in 19 cities.