In particular, a debate between the C#/.NET/IIS stack and the Java/J2EE/Apache/Solaris stack and the PHP/Apache/Linux stack could go on and on for years and years and you’d never find the right answer. That’s because there are so many pros and cons of all these platforms that advocates of each side can debate and debate and never get any closer to the truth, but it sure as heck is a fun debate.
There’s so much evidence that when it comes right down to it, millions of people are building huge business-critical things in C#, Java, PHP, or Python, and while they may have problems, they’re not mission threatening problems.
So how do you decide between C#, Java, PHP, and Python? The only real difference is which one YOU know better. If you have a serious PHP guru on your team who has built several large systems successfully with PHP, you’re going to be a heck of a lot more successful with PHP, not because PHP is a better language than C#, Java, or Python, but because he knows it better