[CentOS] 4.3 to 4.4 and Yum and Upgrade vs. Update

I'm wondering about yum update vs. yum upgrade. The man page says use 
upgrade (actually the obsoletes flag which is set in upgrade and not 
update) when doing something like a linux 8.0 to linux 9 upgrade. 
Something we can't do with CentOS, i.e. 3 to 4. So, is it better to use 
update or upgrade when going from 4.3 to 4.4? Doesn't RedHat call these 
"Quarterly Updates" and not "Quarterly Upgrades"?

And, it seems that the folks having trouble were doing yum upgrade. I'm 
wondering if anyone is experiencing the same difficulties when doing yum 
update?

And --obsoletes.... seems like the man page for yum really doesn't say 
much about what this actually does.. but it sounds like something I 
don't want to use... sounds like it leaves obsoletes laying around?

from man page

 "upgrade
              Is the same as the update command with the --obsoletes 
flag set."

"If the --obsoletes flag is present yum will include package obsoletes 
in its calculations - this  makes  it  better for distro-version 
changes, for example: upgrading from somelinux 8.0 to somelinux 9."

" yum list obsoletes [regexp1] [...]
              List the packages installed on the system that are 
obsoleted by packages in any yum repository listed in the config
              file."

Could this be what's causing the conflicts with sqlite?

And if update vs. upgrade doesn't make any difference (from my first 
question).. Has a 'clear' direction for painless updating emerged?

Best,
John Hinton