The location is unbeatable. The Royal Mile begins right at the doorsteps. We spent a week at Paul's apartment, and it provided a perfect rest place in between our walks around town. During our stay there was a bag pipe player across the street every day, which indeed provided an authentic Scottish atmosphere!
The apartment hadn't been cleaned after the previous guest when we arrived. This seems to have been an oversight and the contact person was very helpful and arranged a fast cleaning when we were getting to know the city. There's a moist smell in the apartment but it wasn't strong enough to bother us too much. The kitchen is well equipped for cooking breakfast or lunch if you don't want to eat out all the time.
As a tip, there are travel agencies arranging bus trips around Scotland that have the pick-up location right across the street! Doesn't get more convenient than that!