Great location for touring: an easy walk to the Castle, train station and Royal Mile. A ton of restaurants and coffee shops nearby - the grocery store right across the street was also really helpful. Plenty of space for a group of six adults. Blair provided clear info and was very responsive to any questions.
One thing to note is the long summer daylight hours. One or two people in our group were sensitive to the early AM light in the apartment - you may want to bring an eye mask if it is an issue for anyone (no black out curtains).