I have been using Ubuntu at home for my desktop, while at work, it has mainly been Redhat.
In recent years, we have not had to build systems at our site, since they were sent to us pre-loaded with the OS, or we just install a CD, run a script, and the OS and associated software self installs. So easy a monkey can do it.
Today I had the chance to set up a server using CentOS. If you do not know, CentOS is basically a Redhat OS with all of the branding removed. CentOS is built from Redhat source code, so it is essentially completely compatible with any Redhat system. I have installed a lot of systems in my earlier days, but have been out of the fresh install game for quite some time since all of our programs and operating systems come pre-loaded. My recent install experience has been confined to just Ubuntu on a couple of home PCs.
Well, as mentioned, today I had a pile of CD's downloaded from the Centos site and proceeded to set up CentOS 5. Everything went as planned. The only difference I noticed was that the disk partitioning portions was not quite as intuitive as with Ubuntu. In addition, the number of CD's that were needed was a little bit of a pain.
I find that the method that Ubuntu uses for software updates a little more intuitive. Plus, it is easier to find information in the internet if something goes wrong. On the plus side, since there are so many initial packages to choose from (with all of the CD's), you get a much more complete installation for development work.
With CentOS, it was a just little struggle to compile some needed software from scratch where a few header files were missing. With Ubuntu, I thing I would have a much greater problem, since it is "desktop centric." Not really a bad thing, just a different focus.