It has already been stated, but I'm going to give a quick dot-point summary of who these plans will "save a lot of money" for. If you meet both criteria, you may very sell save a lot of money:
1) You currently have unlimited voice minutes and (this part's important) you *really do* need unlimited voice minutes.
2) You need very little data per device, or if you have 3 or more devices you need very little data for most of your devices, but maybe need a large amount of data for one of your devices.
Point #2 is pretty straightforward, but I want to highlight point #1. How many people really *need* unlimited voice? For those of you who have unlimited voice minutes (or have a plan with a large bucket of minutes), have you checked to see if you're actually using more than what a lower voice minute plan would give you? In my case, we have three phones and the lowest minute plan (450 I think). I don't think we've ever used more than 450 minutes. Unlimited mobile-to-mobile is a big part of the reason why. And since we never go over, we also get rollover minutes, so now we've got lots of extra minutes in the "bank."
On top of that, I *do* use a lot of data on my iPhone, and my daughter could easily use quite a bit, too, if I hadn't given her strict instructions to use Pandora sparingly when outside the house, and to never use YouTube (even though she still uses it somewhat).
So, for people like me who don't meet *either* of those two criteria, these new plans aren't going to look so hot.
I suspect that many people with high-minute or unlimited-minute plans *don't* need to be on those plans, so they've actually just been wasting money all along that they didn't need to waste. They look at the new plans and think that they're going to save a lot of money, but really they could have already been saving themselves a good chunk of money by switching to a lower-minute plan.