When comparing OneStepBack 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 3rd while OneStepBack is ranked 4th.
Ranked in these QuestionsQuestion Ranking
Pro Easy on the eyes
The color combination has been carefully engineered exactly for the purpose of making people comfortable, while staring at the monitor for a prolonged period of time.
Pro Allows you to focus on what's needed
The design is extremely basic - using just 1 color accompanied by 3 shades of grey, OneStepBack manages to be a very functional theme without adding any flashy.
Pro Follows the material design guidelines
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 Easy installation on Ubuntu
sudo add-apt-repository ppa:tista/adapta
sudo apt-get update
sudo apt-get install adapta-gtk-theme
Not only looks good, but really accelerates work on desktop.
Con Funky arrow button colors in FireFox
The developer is currently aware of this issue, however the fix can't be made until FireFox has an update.
Con No debian support