I think a Disney HM would be fun BUT there are times of year when it's awful -
packed with tourists! Get a TA and do some research on your own to plan the best time to go. The large tour groups (ugh the Brazilians!!!) have really ruined some of our family days there!
http://www.mousesavers.com/
and
http://www.disboards.com/
are two great sites. I think DIS has a whole thread on WDW HMs!