You cannot beat this location! Right in the Grassmarket with direct views of Edinburgh Castle, with tons of awesome restaurants, shops, and activities within a short walk (52 Canoes tiki is pretty rad for chatting up the bartenders, and literally across the street).
The space is fun to enter with a wide spiral staircase taking you up to the flat, and a skeleton key lock. The bedroom is away from the street side, so it's quiet and restful, the kitchen is well appointed and the living area is cozy, with a table and chairs right by the castle view! Only warning is the bathroom is quite cozy, and the shower temp can be a tad temperamental.