There are many excellent reviews on this place and there is little to add: If you are looking for an excellent place where you have a perfect home base for all your excusions to discover Lisboa, just book a room here. The place is great, as is the support by the hosts. I think there are few place that give you such an excellent possibilty to get a close look at the non-touristic side of Lisboa with excellent connections to all the interesting places for tourists as well.
Be aware that the appartment is in a residential area. So you will have all the amenities (shops, restaurants, transportaton). But tere are neighbours as well. Be nice and treat them wih due respect.