When comparing Tomorrow Theme vs Gruvbox, the Slant community recommends Tomorrow Theme for most people. In the question“What are the best color themes for text editors?” Tomorrow Theme is ranked 1st while Gruvbox is ranked 2nd. The most important reason people chose Tomorrow Theme is:
Different colors within the same color scheme to quickly distinguish the layout (px, %, ..) and other declaration blocks from the colors (background-color; color); that eases the visual processing, thus increases reading speed, while reading CSS.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Eases visual processing
Different colors within the same color scheme to quickly distinguish the layout (px, %, ..) and other declaration blocks from the colors (background-color; color); that eases the visual processing, thus increases reading speed, while reading CSS.
Pro Notepad++
Although not mentioned in the list of supported editors, on GitHub you can find a folder Notepad++ with xml files.
Sadly it does not seem to work with newer Notepad++ versions.

Pro Light & dark themes
Dark theme does a good job of contrasting kvps.
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 Comes in 5 different variants
Comes in 5 different variations: Tomorrow, Tomorrow Night, Tomorrow Eighties, Tomorrow Blue and Tomorrow Night Bright.
Pro Multiple contrast options
Three different variants are available, each with different contrasts.
Pro Very easy on the eyes
Both the light and dark version have a reddish background for a consistent look when toggling between them.
Pro Have light and dark version
Dark background has brown-yellowish retro colors, light background is yellowish with pastel highlights.

Pro Made ready for multiple text-editors
Ports for Atom, Sublime, TextMate and Emacs and other text editors are available.
For a full list of available ports.
If you are using a Jetbrains IDE.
Pro You can go all day with Gruvbox
Pro It can be customized in detail
Size of the tabs, icons of file types, contrast of the color schemes, accented colors, indentation in the sidebar, sizes of the status bar and dozens more.
Cons
Con Bad theme
First of all, in the Tomorrow Theme official repository, the IntelliJ Idea theme is just a color scheme. Second of all, it looks very bad on IntelliJ.
Con Looks bad
At least on Neovim.
Con That white is very painful to look at using an F.lux like applications
While it looks quite good for some time, using Night Shift/F.lux applications just makes reading things with Gruvbox quite painful.
