Heavy Graviton Beam fails at being a bonus compared to.
3P Jem'Hadar: Frontal AOE that damages Shields and disables cloak in 6k range.
Feeling, Quite nice. Good Shield damage multiple targets, 2m cooldown.
3P Omega: 50% reduction in DPS and stops the target from turning.
Feeling, Awesome when timed right. Increases entire teams damage, stops the target spinning to face you. 2m cooldown.
3P KHG: 15s Mask Energy Field (cloaking)
Feeling, Kinda lame but better than Graviton Beam, maybe better for Carriers. 2m cooldown.
3P Breen: Energy Siphon
Feeling, pretty weak still better than the Graviton Beam. 2m Cooldown
4p Borg: Tractor Beam with Energy Siphon
Feeling, possibly the only one worse than the Grav beam because it's a 4m cooldown for a lame ability. Might be better if you have Tractor Beam Doffs to drain shields, but at that point you'd have 2 Tractor Beams already.
3P MACO: A Beam that at full Aux doesn't do more damage than a Quantum Torpedo, shuts down Aux for a few seconds and knocks them back slightly.
Feeling, 3m cooldown for what is a Torpedo in Beam form, with a few bonuses, that don't really help.
When the Omega and JH sets have good bonuses and the MACO has one of the weakest it certainly feels unbalanced. I don't think the Aegis has a bonus power.
Set Powers aren't meant to be up there with Boff Powers. They're meant as an additional power that easy to squeeze in, so you don't have to strain your Boffs.
They still shouldn't suck so bad that they are almost entirely ignored by the playerbase.
The Omega set's Gravitic Anchor is right about where a 3rd set bonus power should be, the MACO one is pretty terrible and is never recommended when you could instead have 2 Piece Omega + MACO shield for Tet Glider or 2-3 piece Borg + MACO shield for the heal procs.