My honest answer would be "I can't say..."
I will say that I found PHP easy to learn and use; Java a tad trickier, but you know Java already. I'm not a programmer by education, and only work in code part time in my computer business....
PHP5 is supposed to allow better usage of OOP techniques, but I don't know if it's working well or not. That's where you might find JSP to be superior. You might find out more over at php.net, of course.
That said, my wife uses a JSP web app for her job in the insurance industry that I have always had this gut feeling about --- it'd be quicker in PHP.
My guts are often wrong, tho'.... 😉
Honest, yes; answer, well, you decide....
At least your post gets a reply now.... 🙂 You might ask in the Echo Lounge ... some of the folks in there are bound to have an opinion...as long as they don't think you're trolling flamebaits....