Generally Plasma. I really like the look of Libadwaita applications, but the GNOME desktop is very much a "do it our way, or take a hike" - and some of the interactions that I've seen in the past between the GNOME group and others... well, lets just say whenever I see drama in the Linux community as of recently its always been either with GNOME or Wayland. That doesn't necessarily instill a lot of confidence in me using either of those.
Some Wayland fans like to ignore reality, like the fact 80% of Linux users use Nvidia, or that Nvidia offers a free Linux driver for their own reasons and have zero incentive to open source it, or that even if it weren't for Nvidia we still can't use Wayland because it's not ready and doesn't do everything that X does.
When you ignore reality you tend to get into arguments constantly.
As far as I understand, its the major push for moving forward with Wayland and dropping X11 as fast as possible yet Wayland still doesn't work for a lot of workflows (say, making use of global hotkeys, or Nvidia users, etc).