I missed a flight and needed a last minute overnight stay. This fit the bill perfectly. It's not for everyone. For me, it was excellent. The staff was incredibly friendly, the kitchen privileges were great, the bed was firm, the room and bath spotless, and the A/C and fridge were first class. On the cautionary side, the room is a tad small (no problem for solo travelers or those looking for just bed and bath for the night) and the outside of the building is a bid off-putting. Once inside though, the elevator takes you up to this quiet, well furnished guest house.
As a nice touch, rooms are assigned names not numbers as they don't want their guests to be treated as numbers.
Finally, the guest house is one block off the Marques de Pombal Metro stop so it was easy to take the Metro from the airport to the guest house stop for $3.60 round trip.