AT&T, Verizon Shared Data Plans: Which Is Better?

AT&T and Verizon both recently announced they are shifting their mobile data plans to a shared family model. This change makes sense in view of today's proliferation of data devices and increasing importance of data as compared to voice. Both plans offer a data budget in gigabytes per month shared among all the devices in the plan, along with a fixed cost per device. Conceding the obvious--that voice and texting are a very small part of network usage--the carriers also have made all voice and texting unlimited as part of their plans.

Considering that the new plans bring pricing more in line with the reality of how the devices and networks are used, the new pricing regime could benefit customers. Of course, depending on how the carriers go about it, the new plans could end up costing some users more.

What do we know based on the announcements so far? After comparing the plans, I'd say that Verizon is the better deal for most moderate users. But if you have multiple devices and churn through data, AT&T is cheaper in the long run. For families with lots of devices, either new data plan, from AT&T or Verizon, is a much better choice than current plans. Here's how it breaks out.

AT&T provides numerous tiered options, as shown in the table below. The more devices you add to your plan, the better the deal--at least compared to the per-device plans of today. AT&T estimates that a plan with two smartphones and one 3G-enabled tablet will cost $170 per month on a 6GB plan. (After taxes and regulatory fees count on about $200 per month.)

• AT&T's Shared Data Plan
• Verizon's Shared Data Plan

Verizon has chosen to go a slightly different route with its plan, giving casual users a better break in general. In the table below, Verizon charges a flat $40 a month for each smart phone, regardless of which data package you choose--unlike AT&T, which gives you a break on per-phone fees the more data you buy. However, except at the lowest tier of 1GB, which costs $10 more, Verizon offers cheaper low-use plans than AT&T does. Verizon seems to be geared for moderate users; its plans peter out at 10GB whereas AT&T tops out at 20GB. Verizon says you can get an additional 2GB of data for just $10 a month. (Exact quote: "Need more than 10GB of data? Add 2GB for $10/month by logging in to My Verizon.") What's less clear is whether you can keep adding 2GB more for another $10 per month. If so, Verizon could be the more flexible way to go if your data needs are moderate but growing.

In any case, the middle-of-the-road user of two smartphones and one 3G-enabled tablet on a 6GB plan in our test scenario would fare the same on Verizon--also $170--as he would on AT&T.

The more devices you have, the likelier AT&T will be the better choice because its per-device cost decreases with its most expensive data plans. Let's up the ante and consider a family with four smartphones and two tablets and a 10GB plan. Here AT&T offers a slight edge, costing $260 a month versus $280 for Verizon.

Currently, T-Mobile is my wireless provider. I've got three smartphones and one 4G/HSPA+ hotspot, with 10GB of data, which puts me in a power user bracket. I spend about $425 a month, or roughly $100 per line. I ran the numbers for what I could expect to pay if I switched my four cellular devices over to AT&T or Verizon, calculating both the 6GB and 10GB plan options. It's clear I could save a bundle compared to my old plan and that, again, AT&T's shared data plan has an edge over Verizon's for multiple-device users like me.

Finally, I compared the base cost per gigabyte for each plan, not including the fixed cost per device.

Bottom line? Again, with the exception of the 1GB plan, casual users will spend less per gigabyte with Verizon. But again also--if you plan to use a lot of data, AT&T's greater selection of data levels could help you avoid overages more consistently and predictably.