When comparing Fira Mono vs Hasklig, the Slant community recommends Hasklig for most people. In the question“What are the best programming fonts?” Hasklig is ranked 28th while Fira Mono is ranked 51st.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Looks great and is easy on eyes
Almost looks like Source Code pro and works great with Intelli J where Source Code Pro renders all junk on one of the primary IDE.
Very good for people who read code through out the day.
Pro Extremely readable
You can look at the code for hours and hours. The height between lines and the spacing is perfect.
Pro Offers better performance in some Emacs builds
This font is used by some Emacs users on Mac OS X in order to get better performance.
Pro Great for Haskell
Pro Has a heavier appearance than Fira Code or Monoid
Pro Completely free and open source
Freely available via GitHub, therefore can be modified and improved by anyone.
Pro Has many variants such as Italic, Bold Italic, Light, Semibold, etc., etc
Cons
Con Large line height
Compared to other options, Fira has a high line height, which reduces the number of lines you can see on screen at one time.
Con Lacks !=
Some coding fonts with ligatures, like Fira Code, turn != into ≠, but Hasklig does not. The reason for this is that Hasklig was designed for Haskell code, and so turns /= into ≠ instead.
Con Some Ligatures like -<< don't look that good.
Con Has a heavier appearance than Fira Code or Monoid
Con No support for many editors, including emacs
Unfortunately, not supporting emacs is the number one reason I don't use this font all the time.
Con Very cute but not WYSIWYG
You want to see exactly what you've typed, not have your brain have to do a little dance every time you see one of these artifacts.