This is a great location. Great spot to explore Lisbon from. If you're just looking for a home base, this spot is a good one. I stayed here for 2 weeks.
The apartment is good, but not great. The street its on is noisy at night so one of the bedrooms is pretty loud; you'll want good ear plugs. The wifi isn't good; it only is strong in the living room and even then it's not good enough to work from (which is what we were trying to do). The lock on the front door to the building needs to be repaired. The door can be easily pushed open with out using a key at all. The lock on the door to the actual apartment is very secure, though. One of the showers is too little to comfortably take a shower in, and the other one has a really low rain head, so people over 5'5" can't stand under it.

Lots of little touches throughout the place were missing. There wasn't any hand soap when we got there. The salt and pepper shakers were empty. There weren't many hangers, and there was no drying rack for wet clothes (the dryer did work really well-- I just like to air dry some things).
As other guests have written, you need to go to their office to get the keys. Taking an uber from the airport to their office and then their office to the apartment was annoying. The people at the office were very nice and welcoming, but that extra trip wasn't what we were hankering for when we arrived at the airport.
But it's a lovely apartment. Beds are comfy and the neighborhood feels safe. It's a good spot to stay. But not great.