This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
I think that choosing one over the other based on just this would be the wrong thing to do. I'd prefer to say: which suites you better? Personally I like Java and application servers have some handy features built in for managing authentication and sessions, but PHP has a range of useful tools too.