This is anecdotal evidence but in western Europe[1] Ubuntu Server seems to be vastly more popular than either CentOS or RHEL.
[1] With the exception of Germany, where SUSE Enterprise appears to be most popular.
[1] With the exception of Germany, where SUSE Enterprise appears to be most popular.
I guess only the big old customers stick with SuSE. I don't know a single person anymore using SuSE…
I've recently helped to install a new server farm for a media company. We've choosen Ubuntu 10.04 LTS + chef (opscode) + REE + kvm.