We've stayed with three for a week at Chiho's apartment, and greatly enjoyed the place. Very central location with good transport links (1 min from Metro, start of Tram 28, and 24h taxi stop) The apartments has always-sunny balconies, overseeing the square where the morning starts with Tai Chi and the day ends with cocktails. The apartment and building are new, secure, quiet, and well equipped (nespresso, Bose soundlink, tv, microwave, oven, dishwasher, washing machine, blow dryer, iron, indoor parking possible).
Chiho and Nuno were very friendly and helpful, picked us up from the airport early morning and were very responsive. There's a folder with practical tips and suggestions for day-trips, and I found them both very trustworthy.