The location of this flat is extremely convenient. Just steps from Waverly and the Royal Mile, we could easily walk everywhere we wanted to be. The trade off, of course, is that it can be pretty noisy, especially for the front bedroom, as you can hear everything that happens in the street (you're only up one flight). The back 2 bedrooms seemed to be quieter, especially after 10 or 11 PM.
The flat itself is quite spacious, and has a great view out of the living room. But I'll echo what a previous review said - it feels like the unit is in need of a deep clean and/or a paint job (the walls are pretty banged up, stained carpets, etc.). The pictures make it look very neat and light, but unfortunately we found the reality to be a bit dingier and less well taken care of than we would have hoped.
I'd say this would be a perfectly fine place for a group of young adults looking to be right in the thick of things, but probably not where I'd stay with a family.