Fantastic location along the main thoroughfare of New Town, walkable from the rail station, all the main attractions of Royal Mile, and any shops and conveniences you might need. The lofted bedroom stays quiet despite the location, and everything else is compact but perfectly serviceable.
This is a terrific home base for touring the city, and a great value too. But I have three notes for future guests:
1/ The climb to the bedroom is more ladder than staircase, this may be an issue if you have any physical limitation.
2/ The unit sits above a nail salon and you may detect the occasional whiff of acetone during their operating hours. This was not any real problem for us, but you might be extra sensitive.
3/ We encountered a "bug" in the check-out procedure that left us briefly between a rock and hard place, that is to say trapped in a stairwell. Fortunately the co-host was nearby and able to help us out very quickly. I'm sure this will be fixed for future guests.