Model would be the Repulsive, it's delightful! Shame it doesn't fit the Chaos fleet so well rules-wise with its low speed maybe I should just get another so I can field a little strike force of them... I quite like the model of the Retribution too.
Game-wise though, I really like the Slaughter class cruiser - mad batteries up close, and the speed to get them there! Gotta squadron them though, or they get swamped.