I played expert after my second game, so i really don't know what the game is like below that. Its fun, and the challenge is much greater, making the accomplishment of completing levels much much more satisfying. I hate the use of bots, though. they always get in the way. I rather have a stupid player than a stupid bot anyday. you can atleast convince them NOT to eat the pills.
also, DLC for free on xbox 360 does happen. If you go to the marketplace and into PDZ, you can see that Rare was able to do so. And the reason developers plan DLC is so we can get it out faster. somethings can't get into the game on for release, guys.