KDE. There's just so much awesome stuff under it. Plasma, Krita, Kdenlive, KDE Connect... Most of the bleeding-edge Linux desktop development is happening under KDE.

@jespersh if I can not change your mind, so be it. But for anyone else reading this: that comment is simply wrong.
Krita, Kdenlive and KDE Connect are still unmatched in the open-source space. That's an objective fact.
As for Plasma (the desktop environment), it's not the lightest (nor the heaviest), but it is as close to the all-GUI experience as you can get on Linux.
For anyone who wants to try Plasma instead of blindly hating it because KDE3 looked like ass 10 years ago, download and run KDE Neon in a VM and click around for a few minutes.

I haven't tried Plasma, but KDE Connect is awesome.

Neon is the awesome.

Interesting thread because I'm currently deciding between KDE vs Mate for Ubuntu. I've used both DEs in the past (different distros) and enjoy both, so I guess it comes down to which has more supporting software. Thoughts?

I ended up with Plasma after doing the DIY stuff with OpenBox and i3. Eventually I got tired of all the tinkering to even get my damn fonts to look good.

Switched to plasma and never looked back.

Because of some very old experiences, I had thought that KDE just didn't have the desktop for me, until I tried Plasma 5 in Linux Mint 18.2. I was blown away by the amount of configurability and convenience Plasma offered me right from the start. And them I discovered other KDE software - Amarok, Kate, Gwenview, Spectacle, KDE Connect - and thought "wow, I wish I knew about these a long time ago".

I do agree with @theKarlisK that Plasma is a bit 'overmenued' in places, and its codebase and libraries often seem complicated and troubled. Gnome Shell, on the other hand, I still find basically unusable.

@beganovichh you can disable all the animations in Plasma. Or some of them. You can turn off compositing, so you have a completely 2D, no frills desktop experience. That's the beauty of KDE software - it makes an effort to do things your way.