[tbworld]

Originally Posted by Rik Brown

We are currently running VB 4.2.2 under PHP 5.3.3.

Definitely dump PHP 5.3.3 as that has a nasty exploit in it, unless your server has been patched correctly. Any of the more recent 5.3 versions are fine. PHP v5.3.3 was used on many servers as it worked well with most of the accelerators out there, that is why the host companies tried to stay with it.

You should search the last four weeks (vbulletin.org and vbulletin.com) about PHP v5.4+, you will get a good feel about the pros and cons.

This won't help you, but it will give you one more viewpoint:
We run are own servers: in production we use php5.3 series on development we run v5.3 and v5.4. We still run vbulletin v4.2.0 in production, but we have taken the critical patches from v4.2.1 and v4.2.2.