I should start by saying Killa Bhawan is not for everyone - it is not a 5* hotel with all the mod-cons (the shower could definitely be improved).. that said, it is an amazing experience staying in the walls of the fort and is a beautiful property.
Perhaps more importantly, the staff were fantastically friendly and made us feel very at home - in particular we went to the sister cafe which was excellent.
We also did the desert safari which was fun, though perhaps did not need the full 8 hours (stops en route are missable).