Perfect place to stay and see Porto! The apartment is very clean and nice with everything you need within walking distance. We were delayed through our flights but the lady checking us in was very flexible! Carla was also very accommodating with our checkout schedule as well. I'd definitely stay here again next time I'm in Porto.
Like other reviewers said, it can be a bit noisy at night but nothing a pair of headphones can't fix! Wherever you stay in a central location like this, you'll have the same noise issue, so it's not something specific to Carla's place.