Roman's apartment is perfect to visit central Lisbon. You can reach most of the city on foot from his place or using the nearby Rossio metro station. the apartment is well set up, practical and has all the necessary equipment, including a clothes washer, which we did not use over the 3 days we were there, but which could be very practical for a longer stay.
Two remarks: finding it is a little complicated, G...le maps takes you to the Rua when in fact it is the Travessa, just a block up...The other remark is that access to the apt is up some pretty steep steps so I would not suggest it for anyone with heavy luggage or any sort of walking difficulty.