I suppose that's really up to each person. The Buena Vista theater on the Dream class ships is pretty much the same as any other movie theater. The BV on the Magic class, while a bit more of a challenge, is still nice.
One of our cruises that's what our goal was, to see the movies (it was a particularly good cruise with lots of new movies on it). I think we saw 5 or six of them on a 7 night cruise.