"PHP is as "complete" as it needs to be for us."

It's so complete that it's painful to write in? There's something to be said for languages that focus on a particular application while peripheral features suffer, but the PHP language is in no way superior to Python or Ruby, even in regards to web development, and there's no problem with saying so.

People use PHP because lots of other people know it, and because it's widely available. Those aren't merits of the language itself. Yes, good things can be written in PHP. That doesn't mean the language isn't demonstrably inferior.