I pre-ordered it from Gamestop (being as I work there) and cancelled it today and put my pre-order on Assassin's Creed: Brotherhood. I spent an hour or so in store messing around with it and it just wasn't engaging to me at all, the movement's clunky and while the transformations are nice, the environments aren't particularly interesting. The multi-player plays like a brawl at best, which is okay, but it doesn't seem very deep or long lasting. So I'm going to give it a pass, but maybe I'm just being really harsh on it, plus I'm still really into Battlefield Bad Company 2's multi-player and I think I might just be spoiled. Maybe someone who's had more time with it could share their impressions.
The problem is is that I really wanted this to be a good game, I wanted it to be the Batman:Arkham Asylum of Transformer games, and its just not getting me.
Edit: Its not that the environment's aren't interesting, its that they're too busy, and it distracts me and throws me out of the game.