It's amazing how many times we've watched this in our house in the last two months - it's becoming one of the titles we reach for when we're waiting for the Netflix queue to catch up. We're been going through a period of watching movies about Hollywood, spurred by rewatching The Player. I read some of the book during a long lunch break at Borders, and Art Linson has some very amusing anecdotes which he's translated-not-very-faithfully into the movie screenplay.
Robert De Niro is perfectly-cast in the this role (good to see him in a great part for once), and Bruce Willis does a great job of mocking himself as an egocentric celebrity. Once of the central plots is about an overly violent movie that the studio wants tamed down, and in the book this was Fight Club. In the film, it's called Fiercely by a British director (great performance from Michael Wincott), where they shoot a dog in the final scene. I won't reveal what happens but it's very funny.
Several of the other plot threads are keep the pace moving right on, including a battle over whether Bruce Willis will shave his beard, and his attempt to keep his ex-wife from having other relationships. Overall, a really great way to spend a couple of hours.