Originally Posted by AcidMax

There were a lot of enhancements to php5, security fixes, speed fixes as well as OOP changes. Things like private, public and static functions etc. PHP5 should be used imho over php4, but hosts have done a poor job of getting php5 in the market place. That being said, php5 has major issues like namespaces. To me PHP5 has pretty much died and most of my stuff has been replaced with other languages that are not only faster but much more structured.

PHP6 is going to have a lot of these things fixed supposedly , but I will believe it when I see it.