That discussion keeps popping up from time to time. I do prefer a better performance but most of the time that not even dependent on the language but on the developer. I've seen super fast websites done in PHP and super slow ones done in Java.
Web application performance will have its exceptional cases. But in general, I find Java web application when modestly-well architected, will respond in low tens of milliseconds--and in many cases single-digits--to the vast majority of their routes. A PHP developer would need to be nearly superhuman to accomplish the same level of performance.
