The apartment was large and clean enough, the kitchen could use a some fresh dishes, they seemed old and very used. The walk to the city was around 30-40 minutes not 15 minutes like described.
In my opinion it doesn't fit a family, more suitable for students. Or couples. The Two bed rooms are very nice, clean and comfortable for sleep, the sofabed was terrible. I'd say it should be used for up to four people more. Oh and very very squeecky floors.
We loved Edinburgh though.