It was a fairly seamless upgrade, one of the easier upgrades I've done recently.
5.0.14 was running and stable on CentOS 5.3
I updated CentOS, and managed to get it all patched up.
I downloaded the 6.0.4, and ran the install.sh script, with the flag to ignore the platform.
The whole process took about 20 minutes, and it's now running very well.
It made me smile.