It depends of you're gaming style:
Goliath Is more for.. the offensive style, 5 more guns can make the difference when you use x4 in pvp or even with x2 or x3 on a cube. So when you couple that with a design (sentinel, solace, diminisher..) you can be very very powerful.
But the Aegis has very intrusting skills. It's perfect for team invasion (Best for clan invasion : 4citadel's+4aegis+5goliaths+2vengeance+1spearhead. Adapted with the number or players. If you're a clan of 40 this can be deadly..
). It's better for the defensive style, the hit and run/repair or heal team..etc... You can sure make a cube with it, with my big account that i got hacked, i blowed a cube's *** with vengeance