chaos Icetrapper = super super cheap build that can still run normal atziri (even insta her) and uber atziri as well. It's the build I used at the start of this league and it facerolled everything while costing almost nothing.
chaosorb trapper = expensive (requires ES items + shavronnes) but can even insta uber atziri. This build is for when facerolling 99% of the time is not enough and you want 100% faceroll.
I don't know the pure icetrapper... I see no point in not taking chaos due to how broken it is in bypassing enemy resistances. Not to mention the poison which scales into insane amounts of damage in lategame. And of course chaos is easier when running maps with tons of mods.
Both can run all map mods. So you can run the mods dangerous stuff and vaal ur maps without fear of bricking them so your mappool is gonna be awesome no matter what trapper you take.