An acquaintance from IRC has written a fairly thorough run-down of the reasons why PHP really isn’t the answer to your server-side problems. I’ve heard some of my friends say the same things over the years, and I think his thoughts are worth some consideration.
PHP: a fractal of bad design – fuzzy notepad.
Many defend and apologize for PHP’s shortcomings, when the reality is that with a minimal amount of initial effort, there are options out there.