I loved the Castle Nest! It was so conveniently located that I was in walking distance to most of the places I wanted to visit and a quick bus ride from the rest. It was a little rowdy outside due to the Festival, but that also added to the fun for me - I could hear bagpipes from the space and see the procession after the Royal Military Tattoo :)
As others have mentioned, the building and apartment do smell a bit like smoke and walking up stairs is neceasary, so if you're sensitive to that or have mobility concerns, this might not be a good fit. That being said. I thoroughly enjoyed my stay, the availability of a washer and dryer in-unit, and the drams of whisky and would recommend this Airbnb to all!