When comparing Proggy Clean vs 6x13 fixed, the Slant community recommends 6x13 fixed for most people. In the question“What are the best programming fonts?” 6x13 fixed is ranked 37th while Proggy Clean is ranked 42nd. The most important reason people chose 6x13 fixed is:
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'.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro The easiest to read
All characters are completely readable in the smallest size.
Perfectly usable in terminal and code editors in 12px text size.
Pro Hipster among hipsters
Even hipsters will marvel at this font, praising you as the new hipster lord. It is best at around 19px (tested on Mac). Overall, it has better readability than many default fonts.
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.
Cons
Con Pixelated
This is, of course, intentional; but it can be hard to look at compared to other smooth mono-space fonts.
Con Smallest font sizes hard to read
Fonts less than 11pt start to fail readability tests. 9pt specifically has an additional issue where brackets don't align.
Con Not really good in all font-sizes
Completely clean pixels, no anti-aliasing so its best viewed in (n*12) pixel size.
Bold font-weight is not really good because of small padding between them.
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.