You´re thinking about staying at Alex´ & Dans place? There´s just one simple answer: DO IT! You definitely won´t regret your decision.
I stayed two weeks in Edinburgh, it was just great. I felt immediately home and welcome. I had a really good time there.
Dan picked me up at the airport, we had tea and biscuits, he drove me to the city, told me where to have my fish´n chips - on the first day. We went for a hiking tour, to a car boot sell, for a walk to Cramond and so on. Alex cooked almost every day and I enjoyed even Haggis! He even baked a birthday cake for me!
The apartment is in a very quiet area of Edinburgh (by bus about 20 min from centre, by taxi about 10 min). Room is big, own balcony, own bathroom, everything clean and tidy. Nothing, really nothing to complain.
Stay there! Do it!