A21 is the best 7D2D. Been playing since A18. They keep getting better.
The new POIs and POI overhauls are wonderful. Whoever is responsible for these POIs is an artist. I always get excited when I trader sends me to a new POI I haven't seen yet in A21.
Overhauled Trader Posts look great.
A21 IS FUN! Looting, crafting, killing, mining, defending, questing, exploring, all the mechanics feel solid and rewarding. Looting and crafting aren't mutually exclusive. Sometimes you get lucky and find what you need looting. Sometimes your crafting skills in a category outpace what you are looting. It's a dynamic almost roguelike experience. No 2 playthroughs are the same. There's some knobs to twist to get this just right but it's close.
Lighting is generally much better, and the best I've ever seen. It is weird when a room will darken as you walk into it, though. Overall, I'd say it used to be 25% of the way there. Now it's 90%. The lighting is almost exactly where it ought to be. Just a handful of oddities to work out.
Zombies are smarter than they've ever been. It used to be that you could easily cheese the zombies every horde night. Now I'd describe their behavior more like "swarming ants". I used to feel very confident on horde nights, now I'm at the edge of my seat.
TL;DR
A21 is buzzin