We really enjoyed staying in Sam's flat; the location is very convenient to the town centre, Holyrood Park and Arthur's seat. We walked everywhere, but there were bus stops not too far from the flat. It was very quiet at night. The flat is lovely and nicely decorated; the rooms were spacious , clean and bright.
I didn't find the sofa bed to be very comfortable, however it was fine just for a few nights and it's a very subjective thing; make sure to remind them to make the sofa bed if you need it, as it wasn't when we arrived. I would definitely recommend and stay again if I am back in Edinburgh.