I don't think there is a better place, or better hosts to stay with, in Edinburgh. The apartment itself is comfortable, furnished beautifully and has all the bits and bobs you need to feel right at home. The location and view of the castle is AMAZING. Truly, I've been to Edinburgh multiple times and have never found a better set up. It's right in the middle of great bars and restaurants with a great view, but it quiets down at night and it was so peaceful for sleeping even with the window open. The only thing is that this is not a good spot for anyone with mobility issues or lots of luggage you'll have problems moving upstairs- there are three flights of stairs to get up, but of course that's the price you pay for the view.
The hosts are amazing as well- we stayed there over Christmas and they went to so much trouble to have a Christmas tree delivered and even decorated it for us. I asked if I could compensate them for the trouble/expense and they just asked that we bring an ornament from where we are from so we can be part of Christmases in Edinburgh in future. It was so heart warming. They left a lovely set of food and bottle of wine as a welcome gift, gave excellent recommendations for local sights and restaurants. And when we had trouble getting the fireplace started, they popped right over and set us up in less than 30 mins- it was great.
Can't recommend this spot, or these hosts, more! Thank you!