When comparing MT Andale Mono vs Proggy Clean, the Slant community recommends MT Andale Mono for most people. In the question“What are the best programming fonts?” MT Andale Mono is ranked 32nd while Proggy Clean is ranked 42nd. The most important reason people chose MT Andale Mono is:
It's easy to distinguish "0" from "O", "a" from "o", and "I" from "l" from "1".
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Excellent legibility
It's easy to distinguish "0" from "O", "a" from "o", and "I" from "l" from "1".
Pro Good font variants
Boldface variant is not too heavy while italic face is not too spindly. Andale Mono contrasts with Source Code Pro, which is very similar in the regular font face.
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.
Cons
Con Not pure mono
Bold and italic are too wide, so it's not pure mono in combination with regular font.
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.