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 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 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 Available with Google Web Fonts
Pro Several styles available
The code comes with seven style variants: ExtraLight, Light, Regular, Medium, Semibold, Bold, and Black.
Pro Offers italics
The beta release version of Source Code Pro introduced italicized characters on Jul 18, 2015.
Pro Even spacing
Characters are evenly spaced, making for better readability.
Pro Great in print
The font works particularly well when it is in print.
Pro Version with ligature support for Haskell is available
Pro Powerline symbols included
Powerline symbols are useful for programmers to display a nicer status bar or mode-line on Vim and Emacs.
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 Underscores that are italicized and capitalized disappear
Let's take for instance when you have a final in Java, you usually type it in italics and capitals with underscores: MY_FINAL_CONSTANT, for example. However, Source Code Pro makes the underscore disappear.
Con Dotted zero lacks clarity
Dotted zero characters are less distinct from capital "O" characters than slashed zero characters.
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.