True, YUM does do a good job of auto-upgrading things; but if you'll notice its often many versions behind (for instance, I use YUM to upgrade my PHP4 install, the latest in the CENTOS repo is 4.3.9 wheras the latest in the 4.0 tree is 4.4.4)
An interesting thought I had, I'm not sure if YUM is capable of upgrading "major revisions" (as in from 4.x to 5.x); I say this meerely because I have several services installed that have version conventions like this however it doesn't upgrade them (such as PHP or even MySQL); likely theres an option somewhere, that or it'll just treat it as a new service (which would be bad)
