It's a really good place for a couple to stay in Lisbon. It's in historical district Alfama, pubs and restaurants are all in a foot walk distance as well as the landmarks. Public transit is also available though you'll hardly use it.
The place itself is clean, and offers you a picturesque overview to the old roofs and the river.
Please note that the building doesn't have elevators, so if you have a heavy luggage-be prepared to that.
However, it's an old house, after all, and the price is reasonable.
Would definitely recommend