When comparing Input Mono vs SF Mono, the Slant community recommends SF Mono for most people. In the question“What are the best programming fonts?” SF Mono is ranked 37th while Input Mono is ranked 44th. The most important reason people chose SF Mono is:
Code is very readable at both big and small sizes.
Question Ranking
Pros
Pro Customizable
Many letter-forms are available in Input Mono, the width and line-height of which are changeable. There are also non-monospaced sans and sans-serif forms available.
Pro Free for private use
Pro Great on small-sized, high-resolution screens
Input Mono is designed to look good on HiDPI and low-resolution screens of variable zoom levels.
Pro Large punctuation
The punctuation symbols are larger than in other traditional fonts, making for greater visibility.
Pro Non-monospaced sibling fonts
In addition to the monospaced variant, the Input family of fonts includes serif and non-serif proportional font families.
Pro Clear and dis·tin·guish·a·ble
Code is very readable at both big and small sizes.
Pro Beautiful with high pixel density
Pro Best legible font
This font is legible in every condition.
Cons
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?