Pros: Excellent expansion with good fluff and interesting characters. Magic is balanced nicely with the original rules and is good fun when it back fires.
Cons: Don't take large expensive units with armour as they get annihilated with the magic; I think some units need magic resistance to counteract this.
Verdict: Good expansion to the Empires series but some additional upgrades for Empires units would have been nice. Definitely worth a go if you haven't tried it. A solid 8/10 for the fantasy ruleset.