I've been using MahApps.Metro[1] and MaterialDesignXAML[2]. Those two libraries have made me feel like sticking with WPF until I retire in 5 to 10 years. I'm constantly getting feedback from clients that the applications look so modern. It's been a nice selling point as my niche is rewriting VBA/VB6 engineering software.
Same. WPF in an MVVM pattern is so comfortable to use once it clicks. It has its quirks but for everything there is a workaround once you stick to the pattern.
For the creators of Mahapps I have eternal gratitude.
[1]https://mahapps.com/
[2]http://materialdesigninxaml.net/