centos = old and "stable" however it's versions of PHP are so old they're pretty useless (php 5.1) (roll on centos 6!)
fedora = new and "unstable" fedora has a short life cycle (see
http://fedoraproject.org/wiki/LifeCycle ... _.28EOL.29)
Personally I wouldn't use either of them in a server system, if I had to use one I'd chose centos and get updated rpms from a 3rd party repo (see
http://wiki.centos.org/AdditionalResources/Repositories), fedora's life cycle is too short IMHO to use as a server.
If I were you I'd try and resolve my issues with suhosin and stick with ubuntu/debian.
Alternatively you could try one of the other supported distros I don't know much about them but googling them will provide info on life cycle, php details etc, and someone else that uses them might chirp up here.
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