I can't think of a better location. It's in Old Edinburgh, steps from Grassmarket Square, which has lots of places to eat and drink. And it's a short walk to the Royal Mile and lots of other sights, including the castle. Princes Street is about 12 minutes away on foot. To get there, first you walk up to the Royal Mile and then down. You'll do lots of walking up and down in Edinburgh. That's part of the charm. In fact, David's place is at the midway point of an alleyway. It was a haul wheeling two big suitcases and one carry-on from the train station to his place, though.
David's place is best for a single person or a couple. I stayed there with my daughter and discovered that David had missed my request for a second bed. I had to fashion one. The shower and Internet were good, though.
Not so good was the dryer. I wouldn't recommend having to dry clothes here.
A convenience store on Grassmarket Square sold wall plug-in adapters and umbrellas - both of which we needed.
You get great views of the castle from Grassmarket Square. And visiting the castle is a snap from the place - you just have to climb two sets of stairs.