So what's your favorite heavy support choice and what do you like to do with it?
Me? Tau: Either field broadsides and watch my enemy dedicate their entire shooting phase to trying to kill them while the rest of the forces maneuver for a better line of fire. bwahahaha... or Max out on hammerheads and throw slugs downrange until my opponent is foot slogging, then using submunitions to eat up the rest.
Merc Guard: Manticores. I've learned recently that manticores can fire directly! So what makes your opponent deposit in their pants? Two manticores brought in from reserves and both fired directly with good line of sight.
What do you like to do?