We stayed in Olga's flat for a week during the Fringe Festival. It's very central to the main festival hubs and was a great spot to use as a base while we were there. Despite being so close to all the activity, it's just far enough that you won't be woken up in the night by late night festival goers.
The flat is on the 3rd floor, so expect stairs but it's a much easier climb than some other 3rd floor flats I've stayed in!
Olga was a fantastic host. She was pro-active in communication and quickly responded to any messages. Before arrival, she sent a very detailed PDF on the check-in process and explanatory video on how the locks work which were clear and easily understood.
The room itself was very nice and the bathroom immaculately clean. There were also umbrellas and ponchos provided in the hallway which were very welcome and came in quite handy during the first day we arrived as it poured down.
I would very much endorse Olga as a host and recommend this listing.