When comparing Orion vs Arc, the Slant community recommends Arc for most people. In the question“What are the best gtk3 themes?” Arc is ranked 2nd while Orion is ranked 29th. 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 Plug-ins including Pixlr image editor
Pro Built for front-end development
Orion was developed specifically for front-end development, making it a strong option for front-end developers thanks to features like syntax validation with ESLint and HTML content assist.
Pro Eclipse-like UI
Orion is developed by Eclipse and shares a lot in common with the Eclipse IDE UI.
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.
Cons
Con No runtime environment
Does mostly do file editing, but without good project support, web terminal, build/runtime environment.
Con JavaScript only
Orion currently only supports JavaScript.
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.
