The G.A. Palace is absolutely a 5 Star property. From the moment you arrive, the welcome and assistance of staff (most bi/triingual) is just outstanding. The facility is beautifully decorated and appointed; rooms and suites are spacious, with useful and luxurious amenities. The hotel offers an amazing outdor-indoor pool with loungers, sauna, steam room, spa and fitness room. The breakfast is beyond anything I've experienced with a tremendous choice, all fresh, and staff on hand to greet you and assist, pour beverages .
The Acqua dining rom is superb - we had an absolutely delicious dinner (our table had chicken and vegetarian main dishes), with helpful service for wine selection as we were not too familiar with Portugese wines. They picked a winer! Plus the hotel is certainley within walking distance of best things and areas to take in (although Porto has hills!)
I would absolutely stay here again and can recommend the GA Palace if staying in Porto.