We stayed for four nights in August during the festival/fringe. The flat is right in the centre of things and ideally located to get to all the main fringe sites on foot, nothing was more than a 15 minute walk away. We overlooked the marching band route from the tattoo so had a great view of that too. I'd recommend this place if location is your primary motivation but be aware that the pay-off for location is that it's pretty noisy outside until late into the evening.