I just recently (finally) duped my 4* AA, and I've been finding any excuse to use him. The way his bleed + poison + nurotoxin makes health bars literally melt is almost hypnotic.
I've been enjoying Symbiote Supreme a lot lately. After that SP3 he can melt through health bars with his Bleeds, and that's not even getting into all of the other abilities he gets from having all of his Genetic Blessings active at the same time.