Families with light to moderate data usage are the most likely candidates to find value in the shared-data buckets that AT&T and Verizon offer, says Maggie Reardon, senior writer at CNET.com and author of the site's Ask Maggie column. If one person tends to burn through a couple of gigabytes or more on her own each month, you may want to have her sign up for her own plan, or consider Sprint's unlimited family data plan.
Validas determined that a "well-connected" family of four with typical usage -- including three smartphones, one standard (or feature) phone, two tablets and a mobile hot spot -- would spend about $310 per month with Verizon's Share Everything plan. The tally for a family of four using smart phones with the Sprint Simply Everything family plan, which includes unlimited voice, text and data, starts at $390. But if you keep voice minutes to 1,500 per month, the Sprint price starts at $190 for a family of four.
A family of four who talk and text a lot could spend as little as $120 with T-Mobile's Unlimited Value-Plus plan, in which you bring your own compatible phones to the carrier. The plan includes unlimited text messaging, calling and data, but T-Mobile slows data speeds once you pass a 2GB threshold. For $180, you get 5GB of full-speed data.