I've just finished an extra long stay at OportoView 4, just shy of 500 days. The apartment is very well spec'd with all the conveniences of home, with the only "downside" being that there is no washing machine. I was aware of this beforehand, so it was not a problem for me as there is a laundry close by, but this may be something that needs consideration by future guests.
The space is well appointed with very tasteful furnishings, very chic. The polished concrete units in the kitchen and bathroom make it very easy to keep clean. The bed is comfortable with plenty of bedding and towels provided for my stay. The sofa bed is also very comfortable. One of the great features is the AirCon, great for an Irish guy in the Portuguese summer.
Communication from Andre is great, he was never far away if I had a question or had a need to raise something. During my stay the elevator broke down, but Andre had it fixed in super quick time and was communicating through the process.
Its location and its proximity to Gaia and Porto is ideal. There is a metro stop at the top of the hill, which makes it easy to navigate the 2 citys of Porto and Gaia. There are plenty of restaurants close by, and UberEats is very handy too for a night in without cooking (although all the facilities are there should you need to cook a large meal). Most weekends I would get an Uber to the beach, which is approx €8-10, depending on the beach.
There are some big shopping centres close by, Gaia Shopping, Arrabida Shopping and Via Catarina Shopping. Personally, I preferred Gaia Shopping because of the Continente supermarket. Its approx €4-6 in an Uber/Taxi from the apartment.
All in all, I would return to/recommend OportoView 4, either for a long weekend, or an extended break.