I've read it over and over, and never grow tired of it! The lack of logic in the story is a nice contrast to our world that is too full of cold logic. I find Alice charming, and the rampant wordplay very fun!
This may be the Williamsons' best book.
I've read quite a few of the Elsie books at this point--it's my site that's linked for more info above--and I have a bit of a love/hate relationship with them. Elsie Dinsmore is the antithesis of what we hope to see in the heroines of children's books now, but I don't think she should be forgotten. This book and the ones that followed were tremendously influential.
That said, I wouldn't ever give one of these books to a small child.