It's really not as good as it was hyped up to be.
With the co-op (online) you can't import your own character.
You get to choose a henchman, though you do get to keep the exp and gold you make.
But it's a cool way to hang out with friends.
You only get 8 spells, but you can cast them as an area of effect or single target spell.
But it's fun and I would buy it if you have the extra cash.