When comparing Fira Mono vs Hack, the Slant community recommends Hack for most people. In the question“What are the best programming fonts?” Hack is ranked 5th while Fira Mono is ranked 41st. The most important reason people chose Hack is:
Hack is free for unlimited commercial and non-commercial use. The webfonts are hinted (TrueType instruction set) to optimize display on the screen and are built into all commonly used web font formats with each new release. They include the complete release character set and smaller (filesize) basic Latin subset releases. They are available in the [build directory](https://github.com/chrissimpkins/Hack/tree/master/build) of the repository.
Ranked in these QuestionsQuestion Ranking
Pro Looks great and is easy on eyes
Almost looks like Source Code pro and works great with Intelli J where Source Code Pro renders all junk on one of the primary IDE.
Very good for people who read code through out the day.
Pro Extremely readable
You can look at the code for hours and hours. The height between lines and the spacing is perfect.
Pro Offers better performance in some Emacs builds
This font is used by some Emacs users on Mac OS X in order to get better performance.
Pro Libre webfonts are available in svg, eot, ttf, woff, and woff2 formats
Hack is free for unlimited commercial and non-commercial use. The webfonts are hinted (TrueType instruction set) to optimize display on the screen and are built into all commonly used web font formats with each new release. They include the complete release character set and smaller (filesize) basic Latin subset releases. They are available in the build directory of the repository.
Pro Very readable
Pro Fixes many readability issues in Vera/DejaVu
The tilde symbol ('~'), comma (',') and semicolon (';') glyphs have been modified to be more readable at small sizes and/or on non-HD displays. In addition, the underscore symbol ('_') has been slightly lifted for alignment with surrounding characters.
Pro Based on the tried and tested Bitstream Vera Sans Mono
The fonts are in the Vera Sans Mono lineage with a significant expansion of the character set (which includes Cyrillic and modern Greek character sets), new glyph shapes and modifications of the original glyph shapes, as well as improvements in metrics and hinting/TT instructions to make it more legible at small text sizes used for source code.
The changelog is available here.
Pro Free/Open license
Pro Powerline glyph patch is included
The regular set is patched with Powerline glyphs by default. There is no need to patch the font to use it in Powerline environments.
Pro Source code is released in UFO format
UFO source format is widely supported by all modern font editors if you would like to modify the typeface.
Con Large line height
Compared to other options, Fira has a high line height, which reduces the number of lines you can see on screen at one time.
Con Too similar to DejaVu
See this gif comparison between the two fonts: https://gfycat.com/SomberUnitedGermanshepherd
Con Sometimes difficult to distinguish lowercase "i" and lowercase "l"
When using a higher resolution monitor and a smaller font size, the lowercase "i" and lowercase "l" are very difficult to distinguish. The space between the dot and the remainder of the letter seems to somehow disappear, thereby making it look like a solid line, similar to the lowercase "l".