Incredible comeback from SotS. This is so much better designed across the board (or rather, it feels like it was designed at all).

The two new survivors are incredibly fun to play.
The new environments are quite good. I used to be unsure about the alt path in particular, but I think it's quite good now.
Stavros's take on the RoR soundtrack is heavier, but still very reminiscent of Chris's style, and I welcome it wholeheartedly; it slots right in with the rest of the game.
The new Collective elite type makes me consider my positioning quite a bit and keeps me on my toes.
Most of the items are fairly powerful, but unlike SotS where many of them were just very good on their own without much synergy, the items in AC actually synergize well with each other and are fun to use.

Will definitely have this DLC in my usual rotation going forward.

There is one item I'm not super sure about yet: Faraday Spur. This green item grants such a massive movement speed and jump height buff that it allows most of the vanilla survivors to pillar skip with it and maybe one other item. This seems... a bit too powerful, for a green. The tradeoff of "you lose it if you jump" is not much of a tradeoff since you can trimp, or if you do jump it's not hard to build back up.