In retail you can attack an Aeolus in just about anything on Insane and survive. It's a matter of taking out the defenses on one section before they kill you. In a Pegasus, it's partially luck (killing the AAA beam takes precedence) you just need to dive in fast so that only a few turrets can attack you (side / bottom is usually best) and then take those out. After that its a matter of taping fire down.
Try that in Vassago's Dirge and you're toast. WiH you can still do it to an extent, although it varies from Aeolus to Aeolus. The Hyperions are pretty excellent at killing you at range however, and never mess with a Chimera directly.
Leviathans can actually be a bit more dangerous with four AAA.