For an actual unlimited data plan, $50/month isn't bad - after taxes it might be a bit more expensive than the $60 MetroPCS plan, depending on where you live. The problem is that they've only decided to offer it on an iPhone... Well, unless you were in Chicago or Minneapolis and signed up during the trial phase, when it was open to any phone. The plan itself is actually no-contract, like the T-Mobile postpaid plans.
The advertisement is terrible, though - both with the screaming and for a different reason - it seems to imply that the "iPhone for life" or some kind of phone flexpay plan is tied to the plan. It's not - the only requirement is that you have a Sprint iPhone 6 (which, I wonder if they'll let you do an ESN change after you activate the thing and throw another phone onto the plan).