I only had one night in Pula as I was flying out the next day. I stayed at Most Apartment Type of Hostel-Type. Strange name, I know, but it was a really neat hostel. The owner of the hostel is very kind and takes great car to ensure everyone is comfortable with accommodations and she also gives great recommendations as for local things to do.
The top-rated thing to visit in Pula is the Roman Amphitheater. It's the most complete roman amphitheater in the world and is certainly a site to see! You do have to pay to enter but you can easily walk around the outside to take in the sites.
I went out to dinner with a lovely French women who ordered black risotto. I'd never heard of this dish, but she offered me some, and it's delicious! It's a dish that is commonly served in Croatia, so I recommend giving it a try if you can. It's cooked with squid ink to give it the black color, which may sound unappealing, but the taste makes up for it.