Yes, it's quite a few stairs to the flat, but the views are well worth the trip up! The flat is so conveniently located that on our first night, we stepped out of the building onto the street and ate dinner at a lovely Italian restaurant just a few doors down.
The apartment is in a historic building on the George IV bridge, it's not fancy but absolutely sufficient. Karen kindly supplied us with cereal for the morning, which our kids greatly appreciated.
It really was just great and so convenient that we could slip in and out during the day of visiting the sights on the Royal Mile and Victoria Street.