Can't recommend this apartment highly enough. The location next to the Grassmarket is ideal to explore the city centre and the views of the castle from parts of the apartment are great.
The apartment itself is well furnished, very comfortable and functional. The host is lovely, providing lots of local information prior to our arrival, made the effort to meet us at the gate to show us around (despite our delayed arrival) and had some fresh food such as bread, milk, eggs and juice. The cupboards and fridge were also well stocked with condiments and tea/coffee etc.
Will definitely rebook for our next trip to Edinburgh.