When comparing Ubuntu Mono vs Hack, the Slant community recommends Ubuntu Mono for most people. In the question“What are the best programming fonts?” Ubuntu Mono is ranked 6th while Hack is ranked 9th. The most important reason people chose Ubuntu Mono is:
Line thickness, shape, and spacing help you to recognize characters and words correctly the first time through, without your eyes having to skip back and re-read.
Ranked in these QuestionsQuestion Ranking
Pro Excellent readability
Pro Easily distinguishable characters
There are dotted zeros in Ubuntu Mono so to distinguish from the letter "O", while the lowercase letter "l" is very different from the number "1".
Pro Pleasant aesthetics
The font has a rounded, smooth aesthetic that is particularly appealing.
Pro Legible even at small sizes
The fonts retain legibility and under subpixel rendering at small sizes.
Pro Many languages
1,200 glyphs, 200-250 languages (native languages of 3 billion people).
Pro Open source font
SIL Open Font License.
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 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 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.
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 Very readable
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.
Con Lowercase "m" is weird and stands out
The lowercase "m" in Ubuntu Mono really stands out because of its unusual shape, which disrupts the user's attention when reading.
Con Dotted zero characters less distinguishable
Dotted zero characters are much less distinguishable than those that are slashed.
Con Many characters seem imbalanced
Some of the characters don't feel like they match well which can be distracting.
Con No support for combined unicode characters
For example, x̄ is rendered as x ̄.
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".