Depends on the flash content you're trying to access. If you're looking to do things like Facebook games, it's not going to work. I can't speak of other websites.
Haven't tried to watch movies on this device but I seem to recall reading elsewhere that it's choppy at best. Granted, I don't know if those people were using an overclocked kernal, so that could make a difference.
Atrix 2: Rooted, not yet ROM'd.