AT&T, if you care

Jared Newman at Techland has a comparison of AT&T data plans, which is of interest to Rico because that's what runs his iPad:

Just like Verizon’s Share Everything plans, AT&T’s Mobile Share plans will let users buy a bucket of data to share across several phones, tablets and mobile hotspots. AT&T’s pricing structure is a bit different from Verizon’s, in that the monthly cost for each smartphone on AT&T depends on the size of the data bucket. A 1GB shared plan, for instance, costs $40 for the data plus $45 per phone, while a 20GB plan costs $200 plus $30 per phone.
Otherwise, the pricing is the same as Verizon. All plans include unlimited voice minutes and text messages, and smartphones may be used as mobile hotspots for no extra charge. Each tablet that draws from the data bucket costs $10 per month, and each mobile hotspot or USB stick costs $20 per month. Basic and messaging phones cost $30 per month with unlimited talk and text.Unlike Verizon, AT&T isn’t phasing out its existing plans. New customers can still sign up for individual or family packages without shared data, and existing users can keep buying subsidized phones without losing their unlimited data plans.
To see how AT&T’s shared data plans stack up, I’ve created a couple of charts that compare prices for a handful of scenarios:

Some thoughts: as with Verizon’s shared data plans, AT&T’s basic individual and family plans are always cheaper than comparable shared data plans. I didn’t even show AT&T’s $20 per month, 300MB smartphone data plans, which could save you even more money compared to the shared data plans.
Shared data only makes sense if you’re willing to sacrifice gigabytes in exchange for voice minutes or text messages, or if you already spend a lot on talk and text to begin with. (As social networks and services like iMessage supplant calls and text messages, I suspect this trade-off is becoming less worthwhile.)
Standalone mobile hotspots were always a huge ripoff because AT&T required at least a 5GB plan. They’re now more palatable on a shared data plan, but you’re still better off using your phone as a hotspot instead, especially because it’s free.
The fact that AT&T and Verizon charge $10 per month  for each connected tablet continues to be the most frustrating thing about these plans. The extra charge isn’t justified by the service provided; it only slows the adoption of new connected devices, and defeats the purpose of offering a unified bucket of data in the first place.
At least AT&T is allowing new customers to avoid these plans. If you’re signing up with AT&T and want more than the bare minimum voice minutes and text messages, head to the carrier’s Mobile Share website, and run the math compared to its individual and family plans.