Overall: great value for money, lovely flat, fantastic holiday!
The flat is much larger than the photos make it seem, so it was nice to have our own space after a week in various B&B rooms. It was clean, with clean bedding and towels provided. Heating worked well, and a fully equipped kitchen let us make some of our own meals, with help from David's Intro Pack file that gave us directions to the closest shops and other useful info.
Oh, and getting there, finding keys etc... couldn't have been easier.
The position is perfect for exploring Old Edinburgh, especially if you are going to be walking around like we did. Finding a good place to eat is as easy as going outside, you are right there on the Mile.
If you are a light sleeper, bring earplugs. You are on the Royal Mile after all. It comes with the territory, but it is not too bad - neither of us lost any sleep from the noise. Besides the bed was comfy so that helped.
I'd happily come back to the same spot again. That's probably the most important part of any review!