When comparing adapta-gtk-theme vs Papirus, the Slant community recommends adapta-gtk-theme for most people. In the question“What are the best gtk3 themes?” adapta-gtk-theme is ranked 1st while Papirus is ranked 3rd.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Real dark theme
Pro Follows the material design guidelines
Pro Easy installation on Ubuntu
sudo add-apt-repository ppa:tista/adapta
sudo apt-get update
sudo apt-get install adapta-gtk-theme
Pro Most complete theme
It styles every nook and cranny of the OS UI, even the ugly Java apps look beautiful using this theme.
Pro Ergonomic
Not only looks good, but really accelerates work on desktop.
Pro Sharp, flat, and fresh
All icons look pleasing, especially with the Arc theme.
Pro Familiar
Used on Lubuntu and BunsenLabs, for example.
Pro Active development
Cons
Con No Debian support (sudo apt-get install adapta-gtk-theme)
Con Pertamax
Con Under GNU GPL3
This limits the use elsewhere.
Con Contrast issues / No border around icons
It makes the the fast and makes it simple to add more icons(since you can simply scale them) however the contrast is lost in some situations.
Con No Ideas
It just copies the icon-syle from a different system.
Con Just another material style copy
Con Lacks icon for backintime
Backintime tray icon doesn't display on the panel because Papirus lacks the icon.
