Fantastic location only a 10 minute walk to Princes Street (albeit up a couple of hills, but this is Scotland after all) and not much further to the Royal Mile and Castle. Although close to the attractions it was very quiet at night and suitable for families etc.
The apartment is in a beautiful building in what appears to be a very expensive, nice and safe area of Edinburgh. The apartment itself is spacious and nice, although as mentioned in other reviews the beds may be a squeeze if you are 6ft or above in bedrooms 2&3. My wife and I are both more than 6ft but we were fine in the master bedroom. Also beware of the stairs, if you are less able this would be a problem, but not a big issue otherwise.
Overall a nice apartment in a nice area close to the attractions and tourist areas in Edinburgh, and I would recommend to family and friends.