When comparing Liberation Mono vs SF Mono, the Slant community recommends Liberation Mono for most people. In the question“What are the best programming fonts?” Liberation Mono is ranked 15th while SF Mono is ranked 42nd. The most important reason people chose Liberation Mono is:
Just like Courier New (the metrics of which this font emulates), its line height isn't too big, which results in more lines on the screen, compared to Consolas and several other more popular fonts.
Question Ranking
Pros
Pro Compact line height
Just like Courier New (the metrics of which this font emulates), its line height isn't too big, which results in more lines on the screen, compared to Consolas and several other more popular fonts.
Pro Very readable
Liberation Mono works well with hinting on high-resolution displays.
Pro Has Bold typeface
Pro Clear and dis·tin·guish·a·ble
Code is very readable at both big and small sizes.
Pro Beautiful with high pixel density
Cons
Con Difference between "0" and "O" isn't clear
It can be difficult to tell the difference between the number "0" and the letter "O". However, the Fedora Project has a slightly altered version of Liberation Mono that fixes this with a dotted zero.
Con Slightly difficult to use outside of Xcode, Terminal, or Console
The typeface isn't available in Font Book, etc. unless the user imports the files embedded in the apps above.
Con Apple is locking down this font
It's not open in any sense of the word. It even gives warnings if you try to rip it out of the Terminal.app or Xcode bundles. Obviously, Apple only wants it on their tools. This is such a shame. It should work in other editors, too. It's a beautiful font. Apple open sourced swift, why can't they be open with a monospace font?