Let the Java experts talk about PHP:

"You can be very clever with some scripting languages and do things you can’t do with regular Java," said Mukund Balasubramanian, CTO of Redwood City, CA-based Infravio, a Java and Web services integrator. "If you know how to use a good scripting language, you can save a lot of time and money in development."

That's why I never use Java :-)