My favourite part about Linux is that it's free software. Featurewise I usually like the package management systems, especially pacman on ArchLinux but unfortunatly ArchLinux is a bit too much bleeding-edge and too unstable for my liking. I like that there are different desktop enviroments to choose from (my favourites are GNOME2/MATE but Xfce is also OK) and I'm not forced to change to a fundamentally different GUI just because someone somewhere decides that the old, perfectly functional stuff, was getting boring. The terminal (bash?) is great compared to the Command promt on Windows and I like that many programs have command line interfaces (GUI is nice but for many tasks the command line is more convinient). As a programmer I appriciate that UTF-8 is the default encoding.
Best thing about Linux is the freedom it provides. You want a video editing tool, you just grab it from the repositories. Want an image editing app? You got it from the same place. Same for office suites. No need to go an purchase this and that piece of software. You can argue that the quality of the free software is not good enough. But that's quickly becoming more a myth than a reality. There are other reasons why professionals are using proprietary software. However, as I said, this is quickly changing.
Did you know that the visual effects in "The Man in the High Castle" series are entirely made with the (free software) Blender suite?