I stayed at Monica and Paolo's apartment for three months when I first arrived in Porto, whilst I got settled and looked for somewhere long term to stay. Five days after arrival there was a hard lockdown due to Covid so I spent much of that time in the apartment and got to know it initimately!
Monica and Paolo couldn't have been more helpful and were always on call (they live above) via message or a knock on the door to assist with any questions or queries. Even if they don't know something they will try and find out for you. There was even an internet outage for 15 minutes once (the only time in three months of hard use), and as I had to explain to my school they got confirmation in writing of this from the service provider so I was covered. We were also talking about bread and they brought me a couple of loaves from their favourite baker. They're lovely people.
The space is actually a little bigger than it appears in the photos which was a pleasant surprise. The location is great, most places you want to visit are in 20 minutes walking distance and Boavista itself is a pleasant, safe area. The proximity to Casa Musica is a bonus I think, I'll be able to tell you more when it reopens! There are plenty of ammenities in the locality - supermarkets, shops, restaurants etc. and a laundrette 2 minutes away if you want to stay long term.
The apartment is also well equipped. If Wi-Fi is your thing they have a rock solid (99.999% if the time), lightning fast Fibre Optic connection, which as I'm an online English teacher with a music project & move Gbs of music files around, I can tell you I well and truly tested.
The kitchen is well equipped with a good induction hop and electric oven, dishwasher, coffee machine, kettle and toaster. Again not an issue for holiday lets when you are touring and eating out most of the time, but anyone considering a long term stay, they've got you covered.
The bedroom is at the back of the apartment and when you are in the bedroom all you will hear is your partner's snoring. The bed is enormous, with a soft comfortable mattress (normally I like firmer matresses but I slept like a baby on this).
The bathroom is small but functional and in good order, as is everything in this modern well equipped apartment.
All in all I couldn't have wished for a better hosts and stay when arriving in Porto, well apart from no Covid lockdowns :)