What's up with Denuvo?

simple:

if DENUVO close all your games that you bought and still have DENUVO will be useless because you can't play them.
DENUVO also monitorize what you do with your PC.

that's the most important things with DENUVO

Nothing special, most "facts" about Denuvo are actually myths spread by outraged people against the possibility of devs of gasp trying to protect their work.

Biggest reason is the performance hit. Now it's not clear cut, some times the hit is so minimal that it's no worse than running Steam or any other form of DRM. Other times it can make a game that meets minimum specs for the game, unable to play the game, or it plays like crap.. Depends on your setup, and a bit of luck.. It's enough that I won't knowingly buy a game with it anymore. I also hate Always-on DRM to begin with. If I buy a SP game there is no reason I shouldn't be able to play it offline.

As for opinions on DRM in general, well we all use Steam here, so clearly we accept SOME DRM. My general view with DRM is that if I notice it, it's not working as I feel it should. So always on DRM, ones that give a performance hit, etc, are a no-go for me.