We had a lovely short stay for a few days at Margarida's place. She met us on arrival and went through everything we needed to make our stay comfortable. She had a huge packet of places to go and eat. The veggie restaurant she suggested was amazing! The metro system works very well so you will have no issues getting around. The local wine and port are sensational. I wish we could have taken some back. There are lots of nice little markets in the centre, great for a lunch in the sun. There is a castle with an incredible view of porto, and one of the highest bridge I've ever been on. There are not many bad things to say about Porto, however if you are not a fan of hills maybe stick to your beach holidays.