I stayed at Rui's place some days in a visit in Lisbon. Rui's flat is very cozy and in a nice area - quiet but central. Rui is a extremely welcoming and helpful host. He waited for me, although my plane was late, we had a nice talk during breakfast and he allowed me to store my luggage at his place during a hiking tour in the South.
I can only recommend staying at Rui's place for your time in Lisbon! I had a great time!