If your GT4 vid is anything like the one we have, then it's fair to note that what you're watching isn't actual gameplay. Some of it is gameplay footage, some highly edited, intermixed with a LITTLE CG here and there, and all from replay perspectives. ergo, hardly a fair basis for comparison (e3 demo meant to showcase gameplay and driving physics vs. mix tape designed for eyecatching public display)

IMO, the demo for Forza shows a great deal of potential for an incredible game, but at this stage is not trying to upstage GT4's presentation (the demo doesn't even have any music, yo). Let's let them finish it before we pass judgement, as per usual? :lol