Just played through AG1 + 2.
AG1 had some great moments that put you under pressure and had great arena balance. Really enjoyed it, with some tough additional encounters which caused me almost physical pain, double Archvilles I am looking at you.
AG2 was frustrating more than anything else. Arenas were tight, new mobs didn't feel that well integrated. Most of my deaths were from getting penned into a tight corner, or from cursed prowlers randomly popping up and cursing you, then getting gibbed by the rest of the arena. Escalation encounters weren't really that bad, pretty straightforward. Final boss just felt pants, no real movement, unlike the Marauder where you can gauge distance for the vulnerability, I could never quite pin down the right range for the final fight. 5 phases of pretty samey and frustrating combat which I 1 shot.
Both playthroughs on Ultra Violence. I'll go back to my Nightmare save on the base game and probably go through a Nightmare playthrough on AG1. Not too sure i'll bother with AG2.