This sounds more that your experience with Debian tools is much weaker then with RHEL based ones. The discussion on this is endless, both systems have advantages, I just prefer Debian from majority of reasons.
> "Having to reinstall 100+ servers from CentOS 5 to CentOS 6 will be remembered as the lowest point in my work experience so far."
I've worked with both very extensively, I just don't see this as the case at all if one is well prepared, and wanted to point out that RHEL systems aren't lacking in that respect. I have numerous ubuntu systems that are lined up for a 10.04 -> 12.04 upgrade, and I don't see it as being any more or less difficult than the RHEL 5 -> 6 transitions I've done, just different.