We stayed in the apartment for 3 weeks. Two of us worked during the week and explored Lisbon by evening and at the weekends. It's a really central location and you can walk to the River in about 10 minutes. The apartment has everything you need for a holiday and even to work while you're away. The internet is really fast (although it doesn't quite reach all the way into the bedroom) and the desk is a useful addition. We cooked a few nights and the kitchen was great.
The only issue we had was the noise from the road outside. The apartment is on the 1st floor, and while not a main road, it is quite busy with cars. It could be quite loud during the day, but usually the noise died down by about 10pm so it never really affected our sleep.