I use .NET and J2EE, but recently transitioned to PHP. I immediately jumped on the PHP 5.x bandwagon. Also, I am using PHP-based web application frameworks. One of the technical requirements was it MUST be PHP 5.x, not compatible with 5.x. It would be like using .NET Framework 1.x instead of 3.x. I agree with Clinton, why use PHP 4.x?
Glad to hear it! I know .NET is somewhat powerful yet it's not one of my favorites. I'm an open source guy