Actually, it's one of the most refined games I've ever played. Playing it is like getting a new phone. You're amazed at how smooth the surface is, the UI is breathtaking, but after all it's still the same operating system, with all the shit apps you can download.
Even, though, the dark zone is pretty small, you feel like you're lost in a vast forest, especially at night when there's fog. The PvP is also pretty challenging, because you have no idea what will happen. I was at an extraction zone with three friend and we got surrounded. Five minutes in I was the only one alive. I waited for enemies to reload, then went rambo. Killed like 7 guys like this, one by one. The last one pursued me through a street. Again, I waited for him to reload, threw a grenade, switched to my shotgun and rambo'd him. Everything was lovely once again, so I strolled through the street to find another extraction zone, I was low on health with no medkits. Then I got sniped. All the loot gone. Lost 2 levels.
It's a little bit like Dark Souls in this respect. Punishing, but rewarding. Running in the dark zone alone is a nightmare, though.