Have never been just before or during Christmas, but we did fly out just after Christmas one year and it was wonderful! Up until New Years it was unbelivably busy, but there was such an atmosphere about the place! The decorations where all still up and The Osbourne lights still on, it was wonderful! After News Years Eve - we had the parks almost to ourselves, especially on New Years Day until early afternoon! It was a very strange experience and we got some amazing pictures on Main Street!
As pretty as Christmas is at WDW, I’d rather take in their Christmas atmsphere either November or late December, those crowds are just too crazy right ontop of the holidays for me to really enjoy myself!
And speaking of taking grown up kids - I’m 24, my brother is 19, we’re still heading to WDW with our parents!