When comparing Iris Light vs Elegance Colors, the Slant community recommends Elegance Colors for most people. In the question“What are the best gtk3 themes?” Elegance Colors is ranked 14th while Iris Light is ranked 16th. The most important reason people chose Elegance Colors is:
There is a PPA available for Ubuntu users, which makes installing a breeze. sudo add-apt-repository ppa:satyajit-happy/themes sudo apt-get update && sudo apt-get install gnome-shell-theme-elegance-colors
Ranked in these QuestionsQuestion Ranking
Pro Multi GTK support
Iris supports newer versions of GTK3 (3.10) and also GTK2.
Pro PPA for Ubuntu
There is a PPA available for Ubuntu users, which makes installing a breeze.
sudo add-apt-repository ppa:satyajit-happy/themes sudo apt-get update && sudo apt-get install gnome-shell-theme-elegance-colors
Pro Changes color
Elegance Colors can change it's Gnome Shell theme colors in accordance to the users GTK them, wallpaper or a user defined color.
Con Development not finished
Iris is still in beta so there may still be bugs and other glitches.
The theme project has been abandoned and there has been no activity for the past two years (the last commit was in May 2015).
Con More involved to set up than other themes
Users need to run a command to run a process in the background for the theme to work correctly, which may be more involved than what users are typically looking for in a theme.
Con Doesn't work
Doesn't install and doesn't work.