I had high expectations based on other feedback and was not disappointed. The location on the Grassmarket is fabulous if you want to be in the center of things. The apartment is super clean, spacious, modern, and uncluttered. The bed is King-size and comfortable, bedding and towels are white and hotel-style, which I like. It really felt like a private hotel room with a personal touch. Fiona is super-responsive. I sent an email about an internet issue at 10 pm on a Sunday and she promptly got back to me and worked on a resolution.
While the apartment is away from the street and it is generally pretty quiet, it did get noisy on a Sat eve until 3 am, and you occasionally do hear people above or next door, so if you are a super light sleeper, this might not be for you.