There are multiplexes, and then there are megaplexes. The word itself seems to have originated in recent years among the many languages of western Europe, but it's definitely a part of American culture now.
The idea of the megaplex is to combine the scope of the modern multiplex, a movie theater with several (usually tiny) screens showing several movies at once, with the quality of the old one-screen movie theaters. Megaplexes weigh in between twelve and thirty screens -- at least twice as many as your average multiplex. If a new movie just came out, it may be showing on four or more screens at once, with one starting whenever you feel like walking in. They add stadium seating and very large screens so that lots of people can watch in comfort. If the room doesn't have as many seats as a typical Broadway theater, it generally comes close. For obvious reasons megaplexes only occur near large metropolii.
On top of that, the whole dining experience is enhanced. You can expect to find a coffee shop, a smoothie bar, ice-cream cones, and/or a fast food counter in addition to the usual candy, soda, and popcorn -- not to mention movie-related clothes, toys, and other merchandise. Major restaurant chains like Planet Hollywood may be located indoors. Valet parking may even be provided, an advantage when you think about the parking problems that occur when thirty screens are lit up on the same Saturday night.
In some ways, they succeed at making the movies enjoyable. The buildings are clean, spacious and comfortable, and even if you don't like Starbucks there's something encouraging about seeing the well-dressed servers there as you walk past with your ticket. And in some ways, they go even further than the cramped multiplexes do in making you feel like cattle being herded into pens to consume the cinemé du jour. YMMV.