I have to disagree with this article. PHP is a heavily flawed language. It's very easy to get started with PHP, but there are too many pitfalls that are too easy to fall into.
Most of the "Virtues of PHP" are available in other web languages if you use the right framework. And if you use those languages you'll benefit from the consistency and predictability that come from having a clear design philosophy from the start.
I don't think PHP is a bad language. It's possible to write good software in PHP, and it's possible to work around the flaws if you really know what you're doing. If your software is already written in PHP, it's probably not worth it to throw it out and rebuild it in something else. But I don't think it's worth the trouble if you have a choice, and I think writing new software in PHP should be avoided.
I'll admit I'm not familiar with HHVM and Hack. Maybe they alleviate PHP's problems.
P.S. Most of the points under "The Case Against PHP" are also issues with Javascript. But the difference is that if you're developing a web application, you have to use Javascript. You don't have to use PHP.