We stayed for 6 nights at the Boeira Garden and we enjoyed it, even though everything was far from perfect...
As a Diamond member we received a 1 cat upgrade to a room with a balcony (that was normally 5€ per night extra, so not that much of 'an upgrade' if you ask me).
We didn't push it, even though there were suites available and Mariana from the reception was adorable!
After entering the room, they brought up a small bottle of (nice) port and chocolates, very much appreciated.
The room itself was really nice and had a nice view over the garden and swimming pool, the bathroom on the other hand we found very basic (very poorly finished, cheap floor tiles, no wall tiles in the toilet, I don't think white painted walls in a toilet is a good idea). The toilet also has a separate door but it moves the wrong way so the entrance to the bathroom is blocked if you leave the door open, poor design and it gets annoying after a few days, especially when you want to use the toilet in the middle of the night.
We didn't like the toiletries, for a 5* hotel we expect something that smells really nice, I realize this is very subjective but the toiletries smelled like the kind of toiletries that you find in a dispenser in a 3* hotel.
There is a dolce gusto coffee maker in the machine and it was awful, if you wanted to make a cup of coffee in the morning you had to hold the cup until it was filled up or it would vibrate, move away and fall on the floor, very annoying.

Breakfast was a daily stressful experience, the offerings were good (plenty of choices) but they need a good manager there, there is absolutely no structure. Because of Covid the buffet gets served to you by the staff, most of them are wonderful people but their English skills are so bad that it becomes annoying after a while. Even communicating simple things like 'one piece', '2 slices', 'pancake' or 'strawberry jam' were a struggle. My partner ordered a cappuccino every day and it literally took every day at least 20min (not kidding) to get it! Getting an orange juice fill up or an extra coffee was also a real struggle. I literally had to try and explain them every day (!) what 'sweetener' is (they only give you white sugar when you get your coffee). We also ordered fried eggs on the first morning but it took 30min (after asking another 2 times) to get them. We gave up after that...

The garden and outdoor pool are really nice but there are only about 10-12 loungers, the hotel was quiet full during our stay so by late afternoon (when everyone was back from sightseeing) everybody was lying on the grass on a towel, sorry but this is not very 5*, they must add more loungers because there is space enough. If you want to eat something by the pool all the tables are in full sun, without any umbrellas available...

The public spaces (especially the indoor bar and lobby) are not cozy, the lobby feels a bit like a hospital entrance with white bright lights, low ceilings and plastic plants on the wall, a missed chance especially for a new build 5* hotel.
The area of the hotel we liked, very quiet but still close enough to all the action, an Uber to/from town was also only about 5€ but we mostly walked, to/from the airport an Uber was 15€.

We paid very little for our stay (83€ per room/night) so we still considered it very good value, but if we would have paid 'full price' (160€+ was the going rate during our stay) we would have complained more.

We didn't checkout the indoor pool/spa because we had great weather all week.

We had a lovely holiday and Porto is an amazing city!