We had a great stay in Chiado! Perfectly situated if you want to discover Chiado, Bairro Alto etc. by foot. We loved staying for two nights, as we wanted to check out the lovely little alleys in Bairro Alto but also be able to be in close proximity to Alfama. Tram 28 has a stop right at the end of the street of the accommodation, and the Metro is about 100m away. :) you need to be noise resistant (which I am not, but I used wax er plugs) because Chiado is apparently quite busy in the night hours and there is a LOT of noise/music coming from the streets. Otherwise we can recommend everything else.