I think the El Capitan is a tremendous experience. The organist playing Disney classics before each showing is awesome. The sound system is state of the art and it's really cool seeing a movie in an old Hollywood movie palace. Going to the local cineplex is really nothing like going to El Capitan.
That said, the tickets are more expensive for El Cap. The VIP seating gets you a guaranteed seat, a bucket of popcorn in a "souvenier bucket," and a drink per person. The only line to get these VIP concessions is the one that moves very quickly while each person collects their popcorn and drink. I've also seen a movie there in the general admission section, and you can, if you get there early enough, find comparable seats to the VIP section. VIP tickets also mean that you don't have to line up for seats. You can just show up and they'll show you to your seat.
If you just want to see Up, then your local cineplex or the one in DTD is sufficient. However, if you want more of an experience before the movie, the El Capitan is worth checking out. The organ plays before every showing and is well worth getting there 30 minutes before showtime starts to experience. There's either a character appearance (but no meet and greet) on stage before the movie starts or some kind of live stage show with many Disney and Pixar characters.
I don't hesitate to recommend El Capitan to anyone, though I do think each person should weigh out the costs, both in terms of actual dollars and travel time to and from Los Angeles, before deciding if it's what they want.
