A nice city!
I havn't been spending a lot of time in Antwerp, but I can only recommend, what I have seen! You have beautiful buildings everywhere and it is full of so many nations. After Amsterdam it is the second most international City of the world! It has a chilled atmosphere too.
Insider Tip:Get yourself some belgian fries! Visit the top of the 360° Museum for free for a great view. And Nachtegalenpark is soo beautiful!