I like haemes for the pain tokens and tend to put them on boats with my wyches. I give each a liquifier. Gives me a couple of choices.
1) leave the haeme on the raider and run around on it liquifing stuff.
2) leave with the wyches if I am close enough and not that worried about overwatch. Use the LG in the shooting phase.
3) separate the Haeme from the squad. Use the liquifier gun on a unit and have the wyches do what they can, then the wyches and haeme are different units so the wyches can get their fleet, and if I really am worried about OW, I can charge the haeme first, soak up the OW and then the wyches can get in with less damage.
I also love LG on wrack squads with or without a Haeme. I really like wracks for an objective sitting unit. FNP, go to ground and a LG during overwatch make them fairly good at it.
I have not used Grots so can't comment on that.