Overall this place is definitely worth the stay if your mobility can accommodate it. The location can’t be beat and the flat itself is so beautiful.
I still rated this place 5 stars but I feel it’s important to note two things. First, and I didn’t see this in the reviews I read before booking, the key pickup is at a location ~7 mins walk away from the flat. With luggage and on Edinburgh streets this is significant. This is not disclosed until you complete the check-in questionnaire so we needed to adjust our transportation plan last minute. Not a deal breaker but would have been good to plan for. I feel this should be noted in the listing for transparency.
Second, yes there are 4 flights of stairs which we expected but one should know that the stairs, especially on the lower two floors, are quite uneven, narrow, and spiral so be sure that you can accommodate that physically. We carried up luggage and backpacks without issue.