The apartment was very spacious and clean and was perfect for our visit with my parents and 2 young children. As others have mentioned, a second toilet would be a bonus in the flat.
The location was excellent and we walked wherever we needed to go. It was very convenient to a number of nice restaurants (mum and dad really enjoyed The Wee Restaurant, which is 200m up the hill) and there's a Sainsbury's Local just a few doors down.
Rebecca was very helpful with information about parking and finding a local GP. In the end, we found cheap parking using an app called Just Park through which you can find private spaces to rent.
Definitely a good place to stay for a trip to Edinburgh!