First, the movie. It captured the period in England well, and Wonderland was absolutely as nonsensical as one would hope for, without being slapstick. The Hatter's tea party did look convincingly mad.
At the allegorical level, this is a beautiful story, with Lewis Carroll writing advice to his own children and to everyone else, to follow their dreams, not be afraid of their demons, and to take their future into their own hands. It also tells how love overcomes fear, how in order to go from one opportunity to the next (the door), one has to change themselves, grow smaller, or grow larger to fit the challenge.
The casting was excellent, as were the direction and special effects. I'd recommend parents who don't know the deeper undercurrents of this tale educate themselves before they take their young ones to derive maximum benefit for the kiddies.