Ranked in these QuestionsQuestion Ranking
Pro Easy on user's eyes
The characters in Source Code Pro are easily readable. They have consistent widths across all weights as to not break up words. Commonly used programming symbols (such as various kinds of brackets) are made easily discernible from each other while various punctuation marks are made bigger than normal. This makes them especially good for programmers who keep staring at code for hours.
Pro Legible on all displays
The characters have been made in such a way that they are easily discernible and usable regardless of font size, weight, and display.
Pro Even spacing
Characters are evenly spaced, making for better readability.
Pro Free and open source
The font is licensed under SIL open font license with source code available on GitHub. Being an open source font, it's also reasonable to expect incremental upgrades and additions to character sets and functionality.
Pro Several styles available
The code comes with seven style variants: ExtraLight, Light, Regular, Medium, Semibold, Bold, and Black.
Pro Available with Google Web Fonts
The font is hosted on Google Web Fonts directory, meaning that it can be easily embedded in web pages.
Pro Offers italics
The beta release version of Source Code Pro introduced italicized characters on Jul 18, 2015.
Pro Great in print
The font works particularly well when it is in print.
Pro Version with ligature support for Haskell is available
A version of Source Code Pro with support for common Haskell composite glyphs such as >>= is available here. An editor with ligature support, such as Leksah, is required.
Pro Powerline symbols included
Powerline symbols are useful for programmers to display a nicer status bar or mode-line on Vim and Emacs.
Pro Light and Extra Light weights available
The Light and Extra Light weights make the font less "bold" looking when reading.
Con Ligatures missing but you can try Hasklig font if you want ligature
Con Can be somewhat odd for hex numbers with certain styles
With certain font-size and font-weight combinations (12 pt and regular, for example) capital letters are bigger than integer digits, making hex numbers look weird.
Con Dotted zero lacks clarity
Dotted zero characters are less distinct from capital "O" characters than slashed zero characters.
Con Very difficult to read compared to Consolas or Courier New
The characters are much too widely spaced apart to be easily readable.
Con Incomplete Unicode support
This font is missing many unicode characters used to "beautify" various terminal apps. Also missing are programming ligatures used in some languages.