Overall this flat worked out fine for us. It's cute, with new carpet, new bathroom and kitchen and it's nicely decorated. Check-in was easy and we were able to find it with no problem. It's about a 15-20 minute walk uphill to the Royal Mile and there is a bus stop close by if you would rather not walk. The neighborhood felt a little sketchy however so we were reluctant to go out at night. It's probably fine but when you don't know the area you take precautions.
We were there during the Fringe Festival so the prices were higher on all lodging. We paid $196 a night for this flat but when I looked at it while we were there it was advertised at a much lower rate. The reason I mention this is not to complain about the price, I understand the law of supply and demand, but only to say that I probably had higher expectations than other reviewers given what we were paying. Aside from the neighborhood (which we felt safe in during the day), the flat is on the bottom floor so you hear everyone coming and going through the main door. The staircase outside the door is metal so it's pretty noisy as are the neighbors who were yelling at each other the first day we arrived. Our main issue however was that the flat is very damp. We noticed it when we first arrived but it got worse after showers. When we washed our clothes and hung them to dry it was really bad and our clothes took two days to dry out. Also, the bed is VERY squeaky as mentioned by other reviewers. It woke me up several times a night when I moved.
As I said, overall the flat is as advertised and at under $100 a night, it's a fine place and a good value. Paying close to $200 a night however I might suggest looking around a bit more before you book.