Luis's place is excellent value for the location as you are within a 15 minute (hilly) walk from all major points of interest in Lisbon.
Luis was very helpful in pointing out some local attractions and things to do and is a very gracious host.
The apartment is on the ground-level so there is some street noise as the day gets going - if you are a light sleeper, bring ear plugs! The studio apartment is great for solo travelers or a couple.