This a great place to stay and a good value. Here are the pros and cons.
Apartment:
Pro: Very modern and super spacious. With the automatic locks for both the door and lobby, it was definitely very high tech. I thought it was a great convenience to not have to carry a key around as you rely on a passcode. The inside of the apartment was very large - the largest bedroom we had stayed in throughout our stay in Portugal. Plenty of room for the bed, our luggage, with still space to walk around the bed without having to bump into furniture or squeeze against the walls. Bathroom was very spacious and had multiple access points for privacy. Additionally, the apartment has HUGE windows which lets in tons of natural light and provides you a beautiful view of Avenida da Liberdade. I loved this part a lot as many apartment buildings within the city center face another building or a small side street. The view here is fantastic!
Cons: While the natural light is great for the daytime, the night time was more difficult. The bulbs selected throughout the apartment are brighter on the Kelvin side - which meant that it was more of a white light inside and made things feel a bit sterile in the night time. Also, all the light options were small - small bulbs in the ceiling or from a small floor lamp. This meant night time did not have a great home feel but since you are mostly sleeping that is ok. The water pressure in the shower was also quite low. This helps save water which is understandable - but it was the lowest pressure I had experienced. Additionally, there was pink and black stains in the shower grout which indicated that the cleaning was not super strong.
Location: Pro - great location! You are not too far to walk into the great neighborhoods like Chiado or Principe Real. I think either one took max 15 min - please note that some of these means uphill. The train station is also close by as well. The street itself has lots of food options - with more touristy options like hotel restaurants and padarias, and if you walk by one side street you get lots more smaller and local options. Also there are banana cafe's up and down the street with one directly in front of the lobby door. SUPER convenient if you just want to take a morning coffee (at 10am) or even a late night drink or snack - open till 2am. Also this Avenida is home to all the great shopping brands of the world - if you want to shop for high end goods like Gucci, LV, Prada etc. This is a big step up from the shopping area in Rua da Augosta which is mostly more mass shopping like Zara and Ale Hop. What I like about this area is that because it is more high end, that means when you go home at night it is relatively quiet. My last place was closer to Chiado which means that there was still a lot of foot traffic close by - which is not always bad.
Cons: The banana cafe is a blessing and curse. If you plan to stay at this location from Thurs - Sun note that the banana cafes all stay open till 2am. Not so much an issue in the work week but starting Thursday night, people like to stay and visit the cafes until close. Which means even from inside the apartment you can hear people downstairs that are still drinking and having fun. There is also music - either from a dj or a live musician starting Friday night. If you are a night owl then this isnt a problem - Lisbon is the city that doesnt really sleep. But if you need to sleep early for an early morning, well this can be more difficult.
Overall this is a great stay and would recommend it to anyone as long as you are prepared for late nights at the banana cafe, being a few steps farther from the main center (but not so far as to be a super inconvenience), low water pressure or if you want a more quiet street starting around 7pm. Like I said, the window views and natural light can make up for these short comings.