Mike Portnoy's beats are too jagged and all over the place for it to be progressive, he's a loose cannon when it comes to drumming. He's probably one of the best drummers in the world, but too much can be a bad thing. I'd classify Dream Theatre as a mix between butt rock and new age metal, definitely not Progressive.
Examples here:
Mike Portnoy (Lots of Fancy footwork, not so progressive, kinda made me laugh that in one of these videos he has like 10 snares and symbols he doesn't even use.)
Mike Portnoy Danney Carey (Focused, actually makes use of the drums he needs. Obviously Progressive, very steady and clean, tried to find more vids this is the only one I could find.)
Danny Carey 
