People like micro-optimizations. They are easy to understand, easy to apply... and useless. But some time ago, while reviewing pull requests for Twig, I read an interesting discussion about the performance of the ternary operator in PHP (thanks to @nikic for the investigation). Do you know which [example] snippet is the fastest (of course, they do exactly the same)? The right answer is: it depends.

He notes that it's all about the data being worked with. As some of his tests show (testing code included) there does end up being a difference between using it on a small and large dataset. After investigation, it was found that the ternary operator copies (copy-on-write) the value versus an "if" that just evaluates. He also mentions the new "?" version of the ternary syntax in PHP 5.3, but notes it still suffers from the same issue.