It's a really good spot with a nice view of Lisboa; close to supermarket and not so far from metro and city barycentre. As reccommended by Tin, the bakery/coffe, right below the flat is perfect for breakfast (cheap, excellent and the owner a nice guy).
Yet, the flat is not the most classy I've seen, a bit stinky and the rooms pretty small.
Tin was friendly, just the strenght needed, with a lot of good tips but still doing business.
This is my feedback, make your choice and have fun in Portugal