Good nightlife, but Porto is prettier.
The castle by the sea is worth a visit. Main squares are gigantic. I went during the Vogue Fashion Night Out and it was so cool! Definitely seems like a great party place. The city itself is kind of shabby though.
Insider Tip:Definitely see/hear Fado while you are here. Just make sure you go with someone because I was followed by some guy and the streets there are very small and mazelike. Not recommended if you are a solo female.