I also swore when I saw it.
It looks good, but is it usable? I'd worry about the sims getting to the bathroom in time as it must be a bit of a walk between different parts. Plus getting from a bedroom to the front door for work... can they make it in time or do they end up being late? Also with raising kids if you have to keep moving from one part of the castle to other parts when you have a large family and them all scattered about, it must be hard to keep tabs on everyone. I like to play in quite a controlling way and not let anyone do anything I haven't instructed them to do.
Those would be my concerns anyway, but just for looking at, wow. And I really commend all the hard work that must've gone into it.
I was just thinking over the weekend that I might have a stab at doing buckingham palace but I don't know if I'd have the patience to spend that long on one build. Respect!