The Abbey Hotel is a lovely place in the heart of Edinburgh. It's perfectly located: 3 minutes from Calton Hill, 5 minutes from the Playhouse, 10 minutes from Waverly Station and the old town.
The room I stayed in, while small, was very clean and there was a fantastic shower. The people at Abbey Hotel are extremely friendly and always ready to help. Try the Scottish breakfast, it's excellent!
I would surely recommend Abbey Hotel and I know that, when I return to Edinburgh, this will be the place where I'll be staying!