I just completed my corpsethief claw, but haven't run them yet. I have used scalpel a few times for null deploying and the grotesquerie a good bit.
I find I can pretty well null deploy without scalpel using a couple regular kabalite squads out of LOS, so I don't use them much anymore since ITC limits you to 3 detachments/formations. The grotesquerie is still a favorite of mine though. I usually rush them right up to opponents and if the raider doesn't survive I disembark them using it for cover for added durability. The leadership bubbles alone usually lead to me scaring off a couple tau units or wiping a couple necron units in the first turn.