On his blog today, Andi Gutmans has posted his feelings on the growing trend of PHP developers turnng to the C level of things to add new functionality to the PHP development.
Developing features in PHP not only takes less time, but is also less prone to bugs, easier to maintain, and more stable and secure. Also, in the majority of cases, whether such a feature were implemented in C or PHP, would not make a significant different to overall application performance.
One thing I have noticed, is that quite often, PHP developers who are seeking for new PHP features are prematurely trying to implement them in C. Although, there are definitely cases where you want to write your code in C, I think in some cases PHP is too quickly dismissed.
He gives the example of the ZSearch functionality that they mentioned in the php|architect webcast for the Zend framework - entirely implemented in PHP, not C. He also mentions a point that web developers would do good to take to heart - the bottlenecks usually aren't in the code - it's dealing with external resources that's the problem...