Who has the better unlimited plan? Sprint vs. T-Mobile

With T-Mobile USA poised to offer its own truly unlimited data plan, Sprint Nextel is no longer the only game in town.

The move underscores the competitive environment in the wireless industry, with T-Mobile and Sprint required to go the extra mile in their struggle against larger rivals AT&T and Verizon Wireless, both of which have piled more limitations and restrictions on their own data plans. Sprint has said that its unlimited data plan has been a key differentiating factor against its competitors.

T-Mobile believes it has a strong counterpunch for its rivals with its latest option, but does it really? CNET breaks down the various plans to determine the best deal.

Pricing
T-Mobile has a myriad of options, including different combinations of its "classic" contract plans and its "value" no-contract, unsubsidized phone plans.

Classic contract customers that want the full unlimited offering, which includes a flat-rate on unlimited data, voice minutes, and text messages, pay $89.99 a month. If traditional phone calls aren't that important, the monthly plan goes down to $79.99 with 500 minutes.

Value customers, who can bring their own phones or pay full price for new phones, would pay $74.99 a month for a fully unlimited plan, or $64.99 for a plan with 500 minutes.

Sprint's options are a bit more clean-cut. A $79.99 plan includes 450 minutes, along with unlimited text messages and data. There's a $99.99 option for 900 minutes, and $109.99 for a completely unlimited plan.

Winner: T-Mobile

4G Coverage
T-Mobile previously boasted that it had the largest 4G network in the country, although it has ceded that title to AT&T. While some in the industry argue about whether its definition of 4G jibes with everyone else's, its network speeds are impressive regardless of the technology.

T-Mobile covers 220 million people and nearly 230 markets with its 4G network, which runs on a technology called HSPA+. It plans to build out a faster version of 4G, called LTE, next year.

Sprint, meanwhile, has long relied on a 4G technology called WiMax, though its newer phones don't work on the network. The network, operated by Clearwire, reaches 130 million people and 71 markets.

Sprint is further ahead on its LTE rollout but has so far covered only 16 markets. Most of its newer smartphones run only on LTE and its 3G technology.

Winner: T-Mobile

Handset selection
T-Mobile is at a disadvantage here. Its current flagship smartphone is the Galaxy S3, a device that's available from virtually every other carrier. It also sells the One S, the midtier version of HTC's One series of phones.

T-Mobile also offers its own MyTouch line of smartphones, which have proved to be popular with its base of customers.

Under the value route, consumers can bring their own unlocked iPhones purchased elsewhere and sign up for an unlimited data plan.

Sprint, meanwhile, offers the iPhone 4S, though that phone is able to tap in only to the company's 3G network. It too offers the Galaxy S3 and the Evo 4G LTE, which is comparable to HTC's high-end One X, but both phones are largely 3G devices waiting for the LTE network build-out.

Winner: Sprint

Conclusion On a financial basis, T-Mobile wins at every tier, and offers an even better deal if you're willing to bring in your own phone and forgo a contract.

T-Mobile also addresses the lack of an iPhone with its own Micro SIM card and ability to serve unlocked iPhones, but that's likely too much of a hassle for most customers. Sprint has a superior lineup, even if its phones can't yet take full advantage of the fastest possible network.

Of course, coverage is the real wild card. Customers in the few Sprint LTE markets that are up will have a superior experience. Coverage on either carrier will vary greatly depending on location, time, interference, and local wireless traffic. By the numbers, T-Mobile offers the best deal, but you should do your homework before committing to either unlimited data option.