When comparing SF Mono vs Hack, the Slant community recommends Hack for most people. In the question“What are the best programming fonts?” Hack is ranked 9th while SF Mono is ranked 32nd. 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 Clear and dis·tin·guish·a·ble
Code is very readable at both big and small sizes.
Pro Best legible font
This font is legible in every condition.
Pro Beautiful with high pixel density
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 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 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 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 Very readable
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 Apple is locking down this font
It's not open in any sense of the word. It even gives warnings if you try to rip it out of the Terminal.app or Xcode bundles. Obviously, Apple only wants it on their tools. This is such a shame. It should work in other editors, too. It's a beautiful font. Apple open sourced swift, why can't they be open with a monospace font?
Con Slightly difficult to use outside of Xcode, Terminal, or Console
The typeface isn't available in Font Book, etc. unless the user imports the files embedded in the apps above.
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".
Con Too similar to DejaVu
See this gif comparison between the two fonts: https://gfycat.com/SomberUnitedGermanshepherd