Sorry about the lighting, it isn't really the way I wanted it.
These are the dimensions I got:
Kingdoms castle 32cm wide (40 studs), 24cm (30 studs) deep and 33cm high
New Castle 35cm wide (44 studs), 28cm (35 studs) deep and 37cm high
The Kingdoms castle is slightly smaller, but slightly taller. In my opinion the Kingdoms castle is much better as it has fewer panels, is more fun to build and a more pleasing design. The new castle has 21x Wall 1X4X5 W/Bowed Slit and 18x Wall 3X3X6, Wry 45 Degr. The kingdoms castle only has 16 and 6 of those panels and uses more bricks instead.
Actually the walls are exactly the same height. The problem is the panels in the new castle are set higher and the connecting pins are further in (other than the rear towers of the Kingdoms castle).
The walls are the same height, but the Kingdoms one is set one stud back.
The Kingdoms rear towers aligns perfectly, if the torch doesn’t get in the way.
I have almost all the Fanstasy era sets and all the Kingdoms sets. The Kingdoms castle is my favourite and I have three. I just wanted another different castle even if it wasn’t as good as any of the Fantasy or Kingdoms ones.You may be disappointed in the parts you get though, there is an awful lot of panels compared to the older castle sets.