ATT responding to competition with good mobile data deal?

Unless I'm missing something, ATT appears to be responding to pressure in the industry with a mobile data deal worth looking at for existing customers.

It's at http://att.com/mobilesharevalue

It's offering 10GB/month of data for $100, but then per-device fees that would look to save money for someone who has one of the intermediate data levels (from 2 to 6GB).

I'm on the 1GB plan right now, and while it doesn't save me money, it does up my data tenfold for the same price (and I actually save a bit because of my discount that applies to the data plan, but not the devices).

So, I know you are going to ask. No, I am not shilling for Big Mobile. No inducements, threats, etc. I discovered it yesterday while spending an hour on the phone with a service rep trying to link my old DSL/home phone account with wireless after moving over from Sprint (which probably could have kept me had it just extended my discount to all the charges, not just its data plan). (An hour? Yeah, AT&T's MyATT site is a flaming, inscrutable mess. And the site above is no gem -- while it talks about this plan at the top, when I sign on it's still confusing because in the middle it seems to be giving you the old pricing.)

Anyhow, I scrubbed the fine print pretty thoroughly and couldn't find any trapdoors, so I signed up to change. If you see something I've missed, let me know. Otherwise, it might be worth checking out. But as always, caveat emptor.