You can cast spells at any time, after which you automatically resume your regular attack. They're treated like regular party members, so you can switch to them and use their abilities in fights - wandering around as a Mist Elemental is actually pretty cool. In 6 months I hope to be ashamed of this 4 star rating, but for now this is way above the launch average of the 7 games I've played. Graphics are good enough. Sound doesn't offend.
Story is pointless.
Advancement keeps me hooked. You can summon things. Or just let them attack. Chain 5 or 10 attacks in a row without miss timing your button press a few times and you can kill the bad guy without much damage to yourself. It's harder than it sounds and it gives you a huge reason to pick a faster weapon over more damage.