Disneyland-- and only because it has been maintained better.
In 1996 they added the "Here Comes The Bride" organist to the attic.
As part of the "Haunted Mansion Holiday" construction, the attraction was repaired from top to bottom (new scrims were added, new speakers were installed, light fixtures were replaced, animatronics were improved, etc.)
I certainly like WDW's three additional rooms (hallway of portraits, library, and organist)... but the portraits in the queue are better appreciated there, DL's organist is much more sophisticated, and the busts that "stare at you" are much more convincing when you can walk around them and jump up and down and the eyes still follow you.