We had a great experience staying at Miguelon's apartment. The location is not quite central, but it's about 15-20 mins walk from all the main sites. The apartment was very clean with nice touches such as 3(!!) types of coffee, tea, and some cookies. We shared apartment with another couple. They stayed in the next room and we shared a bathroom with them. It was no problem at all as we never overlapped in our schedules.
I think the main advantage staying at Miguelon's accommodation for us was his help in planning our sightseeing. It was VERY easy as he booked a free tour for us on one of the days. He also pointed out sights that we could visit for every day and had a printout with all the schedules, fees and free days at various museums. I highly recommend to read the materials that he sends in advance. You might be able to book some tours that are very interesting but should be booked in advance.