We had a fabulous 4 night break in March. Sadly weather was rather rainy on this occasion, which is unusual - possibly tail end of Storm Emma - but Lisbon was wonderful and we would love to return another time. Great atmosphere, so much to see and do. Once you get your bearings, places of interest are not so far away from the apartment, all within walking distance really. Day pass for public transport is great value, as are the taxis. Sintra is definitely worth a day trip (hope it is sunny for you as it will be exceptionally more enjoyable). As a group of 5, we asked our taxi driver for his contact details for the return journey and also arranged our trip out to Belem due to the weather - Joaquim was fantastic. Highly recommended.