ABSOLUTELY GREAT!
We had a wondeful stay in Lisbon.
Joao is a very nice host, has plenty of tips to give and is very kind.
His apartment is very lovely, the balcony and its view make you feel in paradise. It is very well situated, not right in the heart of the Bairro Alto (which prevents you from the noise) but in a lovely street where Tram 28 is running.