When comparing Solarized Dark vs Zukitwo, the Slant community recommends Zukitwo for most people. In the question“What are the best Gnome Shell themes?” Zukitwo is ranked 6th while Solarized Dark is ranked 9th. The most important reason people chose Zukitwo is:
Zukitwo theme offers a matching GTK theme to the built in Gnome Shell theme.
Ranked in these QuestionsQuestion Ranking
Pros
Pro There are versions for a lot of applications or it's easy to make your own
There are ready-made packages for Vim, IntelliJ, Emacs, iTerm, etc. If your app isn't supported the website explains clearly what colors are used, so it should be easy to wrap up your own.
Pro It seems that is has been given the most thought
Judging from the description that has been given by the author, it seems that this color scheme has been designed with huge background knowledge about colors and relations between them.
Pro Works well with multiple fonts
Since Solarized has pretty good color separation it's easier to distinguish both thin and bold fonts.
Pro Built in matching GTK theme
Zukitwo theme offers a matching GTK theme to the built in Gnome Shell theme.
Pro Offers PPA for easy install on Ubuntu based distros
Zukitwo offers an Ubuntu PPA for Ubuntu based distros.
sudo add-apt-repository ppa:noobslab/themes
sudo apt-get update
sudo apt-get install zukitwo
Cons
Con Too much blue
People caring about the color intensity in their screens, will notice that this theme is not useful for night use. If you use software like Flux to dim the blues in your screen this theme loses its enchant.
Con Low contrast
Comments for example, have very low contrast against the background which makes it harder to read.
Con Vanilla version doesn't work with htop
Half of the usernames in htop have the same color as the background.
One has to use a patched version of htop.
Con Only supports latest version of Gnome Shell and GTK
Zukitwo only officially supports the latest release of Gnome Shell and GTK.