We stayed for two weeks in Sofia's cozy apartment and had a wonderful time. Although Sofia was not able to be there for our check-in, her friend Irene substituted for her, who was most helpful and patient. Communication was great. The apartment is indeed reachable by taking some steep flights of stairs, but as long as you are not physically impaired you get used to them quite easily. :) The apartment is perfectly located and everyday we were looking forward to coming home to it.
The only small deficit we would mention is that the bathroom might need some slight renovations. We definitely recommend Sofia's apartment. Kind regards!