Allan & Anna's flat is a wonderful base from which to see Edinburgh and Allan & Anna are very kind, thoughtful hosts. We would definitely stay there again.
The flat is spacious with one large bedroom, a living room, a kitchen, a bathroom, and a little dining area off the living room. It provided plenty of room for three adults, though I would not necessarily recommend a larger group. The bed was okay and the pullout couch a bit uncomfortable (as most are), but this was a very minor issue.
As to location, it is true that it takes only about 5-10 minutes walking to get to the bottom of the Royal Mile. However, to get to the heart of Old Town will take closer to 20 minutes. We found that the buses were very accessible and preferred this method of transport when seeking out destinations further along the Royal Mile and closer to the castle, as some members of our group struggled with the large amount of walking. There are also many things close to the flat -- a cute bar/restaurant, a grocery store, Arthur's Seat/Holyrood Park, etc. All in all, a great spot!
Thanks again, Allan & Anna! We enjoyed meeting you and appreciate the hospitality!