Staying at Ana’s place was awesome. It’s just pretty close to the metro (something you appreciate since Lisbon has tons of hills) and Plaça da Comercio, so you are essentially in the center of the city.
The private room is well illuminated and the bed was comfortable.
Ana also has tips for restaurants and things you shouldn't miss eating in Portugal.
The only thing you should notice is that the place is above a bar so it can be a little noisy the night (I didn't have any issue sleeping though).
So, if you're looking for a place near a metro station and in the city center, this is your place.