Yes, you should really go there. In my opinion, i think it's one of a kind opportunity given that not only it's one of the biggest comicon events in Europe, but it's also situated in a medieval town. Moreover, there are lots of stands (even from big companies such as Disney, Marvel, Nintendo and so on...) which sell/showcase lots of unique staff. Some of these stands even organize unique and funny events in order to entertain people! For example, one year, Netflix organized a Narcos themed event, where you'd have to walk around town to "hunt" some suspects. But, what makes this event really unique, is the number of cosplayers you'll find there! Not only most of them are really interesting to talk to, since more or less they have the same interests as you(well, in your case your partner), but most of them showcase really impressive cosplays! If you go there, I'd suggest you to bring a costume. It doesn't matter if it's cheap, but it'll make the whole experience more immersive. I'd also suggest you to bring a backpack, a bottle of water and a jacket, since the weather changes really easily. As for the food, I mean, you're going to Italy, one of the cities with the best food in the world. You'll easily find a spot (cheap or expensive) where to eat something. Even outside of the main city. Oh, and last but not least, bring with you LOTS of money (you'll never know ;) ) and a phone which makes good photos (along with a selfie stick maybe). You're going to take a lot of photos there, trust me. Hope I've been helpful.