User blog comment:Iponce96/Operation Olympus/@comment-4672495-20120816072425/@comment-1388547-20120818142204

I much prefer an Adept for Gold and Platinum, if there's at least one other competent biotic to combo with. Biotic explosions do massive damage, and the weakening effect of Warp or the damage-over-time of Reave/Dark Channel are pretty nice too. (If you have friends who like biotics, a team of 3-4 Adepts can tear through a Gold match very effectively, and stands a decent chance on Platinum even on maps other than Firebase White.)

If there's no other biotic to combo with, another good choice is a duration-spec Infiltrator, for doing objectives and revives while cloaked. I always welcome an Infiltrator on the team because of this -- even if the player isn't good at killing enemies, as long as they can stay alive they can still be very useful in a utility role.

Engineers are decent characters in most matches, and actually quite good against geth (at least the ones with Energy Drain or Overload). Their distraction abilities are handy, especially Decoy, but on Gold or higher I consider them a mid-range class, neither outstandingly good nor bad.

I don't have much respect for the Soldier class, other than the N7 Destroyer. Without the constant, passive bonuses from Devastator Mode, most weapons just don't do enough damage, and the Soldier doesn't have much in the way of secondary abilities (crowd control, utility) to make up for it. Soldiers also don't have any particular synergy with other characters -- a pair of biotics working together can be much more effective than they would be separately, but a Soldier doesn't make his teammates more effective in a similar way. (Carnage/Concussive Shot can detonate tech bursts and fire/cryo explosions, but tech bursts don't do that much damage, and fire/cryo explosions are tricky to get.) That said, the N7 Destroyer can actually dish out some serious damage thanks to Devastator Mode, so if you like shooting things he's worth playing.