The Chosen may hurt a little. I basically found myself dropping everything else to deal with them when they showed up and the game thankfully lets you get away with that by stopping the mission timers while they're around. You'll appreciate the Reaper as a class for Ironman - ridiculously good scouts and give you an almost excessive amount of information to plan.Quote from Donald »5 more hours to download
I will say I wasn't too thrilled with the expansion that had the super powerful enemies you can't turn off. You just have to skip the mission that spawns them. I'm typically doing Ironman and don't want to be randomly KO'd by an uber boss.
Pay attention to how it treats other DLC when you start if you don't want the enemy monarchs - default is to include content without the intro missions. I will say the armor from the archon is one of my favorite pieces of equipment in that game. That combined with one of the new guns gives you an outright broken sniper (always have the high ground, death from above refunds a point when you kill an enemy, unique rifle only takes one action per shot). I could clear half the enemies in a mission in a turn with a single unit a few times.