This is an amazing place to stay. Right at the top of the Royal Mile, access to everything so close. The views are incredible and the apartment is spacious and comfortable. We never felt like we were wanting for anything. We made it our base for ten days and just walked to the busses or trains, or up and down the Royal Mile and to Edinburgh Castle.
One thing to be aware of is that it's up a pretty steep hill (it's on the Castle's hill after all) so walking up to it the first day with our luggage in tow was a challenge. (The owner advised us to take a taxi up the hill but we decided to walk, so that's on us.) But after that first day with the luggage we made the walk all the time and had no trouble.
We cannot recommend this apartment enough! We can't wait to book it again!