not true 1080i. It rendered, I believe, a 480p image, blew it up to a 960i image, and then drew black bars around the side to expand it to 1080i.

And, to answer your question: Grapically, god yes. It's beautiful to even watch the compressed videos on the internet. Gameplay, it's mostly the same, and that's why I think they've released this as a tech demo and are concentrating on a whole new GT.