The way the new plan, effective June 28, works is first you add all of the devices to the plan for a fee which all get unlimited voice and messaging. This monthly fee depends on the type of device, with smartphones costing $40, laptops $20, and tablets $10. All devices then share a bucket of data which ranges from 1GB for $50 to 10GB for $100.
This is not cheap but is more economical than the individual plans required before the Share Everything plan. A family of four with smartphones and two tablets will run $160 for the phones and another $20 for the tablets. You would then likely need a lot of data to share so with the 10GB maximum plan you'd end up paying $280 per month.
Not cheap, but cheaper than the 6 different data plans currently required. Especially when you account for the free mobile hotspot that is included, meaning any of the smartphones can be used as a mobile hotspot for other devices.