Postfix 2.3.3 that comes with RH/CentOS is very old, there are lots of new features in newer versions that appear to be very useful (revised queue manager with better scheduler as far back as v2.5, etc.).
Latest stable version is 2.7. I was looking for RPM packages and I've found this site:
Anybody using it? Good things, bad things?...
Anybody using Postfix 2.7 on CentOS by the way? Do you have any observations?