Re: In my experience...
"No, but a well designed one makes it possible to write analysis tools that can point to areas of concern."
...which is utterly irrelevant if you're surrounded by crap developers.
Sure, it's not perfect. Bless it's cotton socks, the most-used versions of PHP have yet to offer stong type enforcement (or what PHP calls 'type hinting' for fear of upsetting the old-timers) of simple types in methods for those times when it's what you want.
But in the end, PHP has all you need to develop rich, stable, tested, maintainable web applications, and it's kept the things which made it great in the beginning such as its practical and powerful associative array-handling and fabulous range of practical functions. When web developing, base64-encoding is a single function away. As is converting JSON to associative PHP arrays. As is sending a blooming email.
In short, PHP is good enough to engineer good systems. The risk factor of your project is entirely settled within the capabilities of your developers. Immersing bad developers in the environment of Java, C#. C++ or whatever will not in any way protect you from disaster. (Nor will it when they're using PHP).
If you want your project to turn out well, get good developers. Chucking out the PHP isn't the thing that'll make the difference*.
(*the caveat here is that there are plenty of applications where a properly compiled application in full charge of its own memory handling (sorry Java) will run rings in performance terms around PHP, but that's irrelevant for web applications where the largest latencies are often tied to data management or calls to 3rd-party APIs.