Yeah, the dwarven dragons are cool, although I now like the Chaos Dragon because of the versatility of its upgrade. Sometimes, you need a little magic resistance (which you don't need against Orcs), and the "lazy griffin" attack is just insane, dealing the most damage among the 7-level creatures, and it's also quite durable. I can only imagine what would happen if you berserk it – it would send half an army to the graveyard! So, you need to use it carefully.