PHP Sucks But I Like It 14 years ago
I think the PHP documentation is the major thing not mentioned here for the non-programmer layman (like me, who uses PHP).
Need to know how to use in_array?
http://us.php.net/manual/en/function.in-array.php
Not only is there a quick reference on the top, but clear, concise, and diverse examples on how to use it if you don't want to spend time thinking about how to work the arguments.
Maybe the expert programmer doesn't really care about these qualities, because javadoc is "easy" to them, but it doesn't compare to this for me.
P.S. As someone who has dabbled with Ruby, Python, etc. I do acknowledge they are vastly superior languages in many respects.