I fought a Khrone themed army a little while back with m LatD. Pretty much we just bashed into each other and them started rolling tons of attack dice every turn. I beat him down on my right flank when my Lord of Change beat his Blood Thirster in combat, though his demon prince (barely passing an Inv. Save from gift of chaos) was rapidly chewing through mutants on my left flank.
Then the 10 man blood letter unit came into play.
In the end it was a draw, I knew a few things to keep in mind for later use, mainly to big out Mr.Demon later, not sooner.
More often then not, I treat it as a fight against marines, as essentially the enemy troops are normally the same stats. Though I do enjoy fighting chaos more as they tend to be more assaulty, and I like it when people come to my slow plague zombies and Spawn.