When comparing Arc vs Papirus, the Slant community recommends Arc for most people. In the question“What are the best gtk3 themes?” Arc is ranked 2nd while Papirus is ranked 3rd. The most important reason people chose Arc is:
Users will be able to match their gtk2 and gtk3 themes easily due to Arc supporting both.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Has both GTK2 and GTK 3 support
Users will be able to match their gtk2 and gtk3 themes easily due to Arc supporting both.
Pro Really clean and nice-looking
Pro Supports gnome-shell
Pro Customizable to dark or light themes
Pro Available firefox and chromium themes
There are matching themes for Firefox and Chromium for those that want to have a fully matched looking environment.
Pro Actively maintained
Actively maintained, support for it won't be going anywhere anytime soon.
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 Has some contrast issues
The theme is a low contrast theme so it really depends on the screen brightness if you see borders or the text, some elements don't even have borders - this makes the theme barely usable for portable devices.
Con Bleak font colors that cause eye strain
The font color in Arc and Arc-Darker is not black, but lightgray
after prolonged usage, it becomes apparent that this font color, combined with white backgrounds causes too much eye strain
Con Close button is not activated when cursor is moved to the top edge of the screen
The simplest of all ergonomic design principles is not followed.
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.