The location is phenomenal, right on the Mound. It's near all of Old Town and all of New Town. The apartment is full of charming art (some created by Rachel) and books, especially Edinburgh guidebooks and novels set in Edinburgh. Everything works well (full kitchen) and everything is comfortable.
There's an elevator from the second floor to the fourth floor.
Be prepared for noise; the Tattoo guns and fireworks at 10:30 every night sound like they are right outside the window; and the walls between apartments are thin enough that we could hear the neighbor's TV. But those are very small complaints about a heavenly experience.