I stayed for two and a half weeks in Patrícia & Rui's lovely Porto apartment and can highly recommend it.
The bed is comfy, the shower is hot, the kitchen is well-stocked and the apartment is just lovely. It's near everything you need and the hosts are incredibly accommodating.
I also work for myself online and can report that the internet is excellent.
If you're a light sleeper then you can hear people in the street and traffic from the bedroom but it's on a relatively busy road and opposite a small cinema so is to be expected. The area is really good though and I would stay there again.