really enjoyed your review. I prefer the 4842 too visually, it looks so much nicer and more rooms, but 4709 is a gem of a castle (plus £100 cheaper).
My initial thought is the 4709 is surprisingly small. The Eurobrick review and others make it look bigger than it is, close photography is effective and Queen Brick is smaller than she looks!
People mention other castle have even smaller rooms, so perhaps this was the best choice (perhaps not for display but for playing with, the latter being most important for my kids.
That said, 4709 has too little that relates to the movies, that said, the castle has been upgraded with a new lego 4842 style roof, columns of clear glass bricks for windows for the great hall, gold plates and goblets for the food, plus extra base plates to expand the great hall to permit another 2 house tables to fit (shame Huffle and Raven logos aren't available). I know, extra expense, but 4709 looks even better now. I also found a load of furniture and a crystal ball from my daughter's Lego Friends sets to make the Gryffinder common room look usable and turned the room below the astronomy tower into Trelawney's class.
Snape's classroom and Slytherin Common room look like a certain bet, and especially as they're designed to fit under the 4709. The Owlery and rotating fireplace look redundant, I think I may salvage that turn it into Dumbledore's office with some bits from the Lego Friends set that's lying around everywhere. Maybe use the rotating fireplace mechanism to turn it into a magical vanishing cabinet that actually vanishes, how I love Lego.
