The flat was really incredible. It is very spacious, with two large bedrooms, a lounge and a huge kitchen - it really is a very comfortable place for four people to stay at. The location is great, very close to the main street of Old Town (like 100m to the corner close) and there was not a lot of noise at night. The place was very clean and everything that we could possibly need was provided. The directions to get there and the instructions to get in were very simple and worked perfectly. Overall I am incredibly pleased with the place and would happily return to the flat if I was ever in Edinburgh!
The only comment I could have on improvement is if there were block-out blinds on the windows in the bedrooms for sunlight. The windows are large and let in a lot of light, and my wife would have liked to sleep in a few mornings, but the rooms get very bright very early. Maybe this was just a case of unusually good weather in Scotland while we were there, but honestly not that big of an issue in a very pleasant stay...