When comparing 6x13 fixed vs Hack, the Slant community recommends Hack for most people. In the question“What are the best programming fonts?” Hack is ranked 9th while 6x13 fixed is ranked 28th. The most important reason people chose Hack is:
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](https://github.com/chrissimpkins/Hack/blob/master/CHANGELOG.md).
Ranked in these QuestionsQuestion Ranking
Pro Well designed
6x13 fixed is the apex of bitmap fonts. It has a nice, defined character set and great proportions for quantity of text onscreen, making for excellent readability. It is aesthetically pleasing for a bitmap font and has been deservedly termed 'classic'.
Pro Legible at small sizes
At a small text size, each character has a limited resolution. A character size of 6x13 pixels means only 78 pixels per character. Modern fonts are designed to be scalable and are less legible at these small sizes. Using bitmap fonts increases legibility by eliminating scaling and sub-pixel aliasing artifacts. Some scalable fonts include "ppems" embedded bitmaps for this reason.
Pro Available on every X server
6x13 is the classic fixed monospace bitmap font that is expected to be available on every X server. It is part of the misc-fixed family. These fonts were handcrafted for readability in a terminal.
Pro Widely available
It is distributed alongside the X Window System.
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 Doesn't have a slashed zero
The absence of non-slashed zeroes makes it harder to distinguish "0" from the letter "O".
Con Extremely small on high-DPI screens
While it is crafted for a screen where the pixels are visible, bitmap fonts do not work well on high-DPI screens as they do not scale too well.
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".