This is the first thing that I've heard of that would possibly make Playstation + wothwhile to purchase to me. Since it's only 1 thing, that's not enough for me, but it does show Sony hasn't given up on the concept yet. It's a slight risk for them to take as they could lose a bit of sales on the game if not everyone can play the demo, but I don't think it's much of one with such a strong franchise.
And before any fanboys freak out, I love my PS3 -- but for me, Playstation + just doesn't offer enough to be a good value. They need to bring a lot more to the table before I sign up.