When comparing Iris vs adapta-gtk-theme, 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 Iris is ranked 10th.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Purchasable filters to heighten visibility in certain conditions
Iris has filters that can be purchased through in app purchases that allow for increased visibility in certain lighting situations.
Pro Easily turned on and off
Iris has a quick toggle in the notification drawer with allows for the user to easily turn on and off the function of the app.
Pro Puts an overlay of your camera feed on top of all other apps
By overlaying what the camera sees over any app on the device, users can see what is in front of them while still looking at their screen, retaining all the functionality of every app or game they use.
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.
Cons
Con No Debian support (sudo apt-get install adapta-gtk-theme)
Con Pertamax
