We stayed at Greg & Jo's place for three nights. It's a gorgeous apartment with a pretty city view, in a really good location for all the touristy bits and very conveniently located for anyone arriving by air or rail. We'd highly recommend the place to anyone visiting Edinburgh.
Two very minor nit-picky complaints: firstly we just had a single toilet roll in the apartment for a three night stay. Secondly we'd have appreciated a slightly wider selection of glassware - there was just one wine glass.
Very minor complaints though, definitely a 5* experience overall.