Just curious for people who have used both extensively, are there any benefits or drawbacks to using 13 compared to 12? is 13 more of a resource hog?

 

I didn't feel any difference between Nuendo 12 and Nuendo 13. And to me it seems that Nuendo 14 even is a little snappier than previous versions (I guess they updated some gui rendering stuff?).
As Nuendo shares the same codebase with Cubase it most definitely is the same with Cubase.
I would even go as far and recommend updating to the latest version (14)