The Decision

Let’s say the rumors are true – even the outlandish ones – and the next iPhone is unveiled later this month and ships to all four major US carriers in early October. Assuming the carriers in question offer iPhone 5 with their current plans, I’ll be dropping AT&T like the Steelers trying to carry the football yesterday and moving to T-Mobile. Here’s why:

Two-line family plan with unlimited voice, text and data for $99.98/month. Done. Data isn’t capped, but is throttled after 2GB/month, which is fine with me because I rarely if ever use that much mobile data (I’m almost always within Wi-Fi range). If T-Mo gets the next iPhone and offers this deal, I’m there unless something new and better comes along by then.

The Breakdown

I currently pay for a two-line iPhone 4 plan on AT&T. We would have switched to Verizon when they got the phone, but one of our two lines was still locked into a contract, and it wasn’t worth paying an ETF to move to Big Red. AT&T’s service in the Bay Area can be immensely frustrating, but it’s much better where we live in Oakland than in downtown San Francisco (where neither of us goes all that often), so we figured we’d just wait out our contract.

When the new iPhone comes out, we’ll be eligible to cancel service without a penalty. I’ll wind up buying an iPhone 5 for work purposes, and we should be able to sell our two iPhone 4s for enough to cover the cost of picking up a second iPhone 5 for my wife (it’s her phone of choice as well as mine right now). So making a move won’t cost us much, if anything at all, out of pocket. Instead, it’ll be a matter of “which carrier offers the best combination of service and value.” You know, like cell phone shopping is supposed to be.

Verizon offers the best overall service where we live and work, but Sprint and T-Mobile are also both pretty good. Let’s get crazy for a moment and imagine that the next iPhone supports so-called 4G data speeds across all four carriers (even though it may not). Verizon’s LTE network has proven fastest in my usage over the past several months, followed by T-Mobile’s HSPA+, Sprint’s WiMax, and last-but-catching-up, AT&T’s HSPA+. That order could change dramatically over the next twelve months with AT&T’s LTE rollout, but for now Big Red rules the roost. Honestly, though, T-Mo’s not all that far behind out here in the Bay Area, and depending on where I am, I’m getting pretty fast speeds right now using Magenta’s latest “4G” devices.

As far as speed’s concerned, then, Verizon and T-Mobile are at the front of the pack (again, assuming the next iPhone supports 4G across all four carriers). Theoretically, three of the four carriers could support simultaneous voice and data on iPhone 5, as it’s a standard feature of GSM networks (AT&T, T-Mo) and Verizon’s HTC Thunderbolt can do the dance on both 4G and 3G networks. Sprint’s current offerings can only do voice and data at the same time in 4G or Wi-Fi coverage zones, which isn’t necessarily a dealbreaker for me, but does warrant a check in the “cons” column for the Now Network.

So now we’re on to price. Currently we’re paying AT&T around $170/month for two iPhones sharing 1400 minutes with unlimited data and messaging. That price is after an alumni discount but also includes taxes. A new AT&T plan with 1400 minutes, unlimited messaging, and 2GB of data per phone would run $169.99/month (before tax). T-Mobile’s $99.98/month (before tax) plan blows that out of the water, alumni discounts or not. Verizon Wireless currently charges a whopping $179.98 to share 1400 minutes across two iPhones with 2GB of data each and unlimited messaging. Sprint clocks in at $149.99/month (before tax) for a two-line plan sharing 1500 minutes with unlimited data and messaging – that’s $129.99 plus a $10/mo. “Premium Data” fee for each device.

In terms of price, and price alone, T-Mobile is the clear winner with Sprint coming in second at 50% more per month and AT&T/VZW trailing well behind. Combine that with T-Mo’s competitive HSPA+ performance in my area and their support for simultaneous voice/data, and it’s really a no-brainer provided things stay the same as they are now. And, y’know, provided Magenta actually gets the iPhone 5.

Those are huge ifs. As AT&T can tell you, adding an iPhone to your lineup can place a huge strain on your network infrastructure. So if T-Mo and Apple do start working together this fall, that speedy HSPA+ data could grind to a halt as legions of budget-minded hipsters sign up for iPhone 5s on T-Mobile. Same goes for Sprint’s network, particularly if they wind up as the only carrier to offer Apple’s device with true unlimited/unthrottled data.

But, hey, Apple hasn’t even announced a next-gen iPhone, let alone which carriers will be selling it in the U.S. So this is pure speculation for now. And in the land of speculation, with all four major carriers getting more or less the same version of iPhone 5 and offering it with current rate plan options, my choice is an absolute no-brainer: $100 per month for unlimited voice, messaging and (throttled after 2GB) data? Are you kidding? Sign me up.

If, that is, I can get an iPhone 5 with that plan. That’s a big if. And somehow I get the feeling if T-Mobile does get the next iPhone, this plan might disappear just before launch day (it is a “limited time offer,” after all). We’ll just have to wait and see.