So, as per the title of thread, why would you select BGV, relic/normal terminators or aggressors? What do you see as the strengths and weaknesses of each for your chapter?
I play RG
successor. I run normal terminators with cyclone missile launches, relic terminators with combi-bolters and LCs
+ grenade harness and aggressors. I find the terminators native deepstrike great for teleporting in turn 2 for a contested objective or to reinforce a unit of mine that needs help. I find it can contribute in both the shooting and melee phases, and the CML
pitches in with AT
firepower. I like the aggressors as they can advance, shoot, melee and are good for the master of ambush strat, and are positively deadly in the tactical doctrine when the +1 to hit and +1 to wound vs characters is active.
Relic terminators I teleport forward in turn 2 to back up the aggressors (if needed), or deploy forward on the board to provide more anti-infantry firepower with the aggressors and act genuine anti-charge deterrent, allowing me to holt or significantly slow my opponents forward movement towards objectives.
What I like about all three units is that they can contribute decently in both the shooting and melee phases, are are durable. Whereas my experience with BGV to date is that they don't do much in shooting (but can shoot in combat, so that is something), are just as durable and better in melee.... but don't seem to act as good as a 'solid brick wall' as blobs of Aggressors or Terminators, at least for me.
Looking forward to hearing your opinions and experiences