We stayed for 3 nights. I was extremely impressed with the location and couldn't believe how close we were to the castle, it was ideal for exploring Edinburgh. We didn't actually spend much time in the flat itself but it was nice knowing we were never more than a 20 minute walk away to get back.
The only negative experience was the broken shower door in the bathroom which made entering and exiting the shower very difficult and also left a gap where water would drench the floor, and this is the only reason I wouldn't rate 5 stars.
We had a great time overall, thank you