I've used a lot of different Linux variants over the years, and I've always ended up coming back to openSUSE and SUSE Linux Enterprise for one reason or another.
Some history on the operating system I used for production servers.
2006 - SUSE Enterprise 9 (mainly because of ReiserFS)
2011 - openSUSE 11 (ReiserFS more or less stagnated and wanted to get on ext4)
2012 - SUSE Enterprise 11 (new servers have Infiniband, which openSUSE didn't support, SLE11 didn't support ext4, so back to ext3... boo)
So at this point I have SUSE Enterprise so hacked up that it's a dependency nightmare. Like it had a super old version of OpenSSL that didn't support new SSL sites, so I had to upgrade OpenSSL, which broke some other things that I didn't care that much about to muck with.
Anyway... finally got annoyed with how hacked up I made the operating system to do the things I needed it to do. So I went looking for a new operating system that supported Infiniband properly.... looked at all the normal stuff (Debian, CentOS, Fedora, Ubuntu, etc.)
During this, I ran across something interesting... openSUSE took a completely different turn a few months ago. It's now based on SUSE Linux Enterprise, but not stuck in the stone age (the enterprise stuff seems like everything needs to be tested for 15 years in case you needed to fly a nuclear power plant to the sun and back and have it never fail), like why it only finally started supporting ext4.
So I gave it a whirl... and the short version is that it's great. I takes all the enterprise stuff I need from SUSE Linux Enterprise (things like Infiniband hardware support), but gives you more modern packages that don't go through years of testing. And it also dumps a lot of legacy stuff that most people don't care about (for example it's a 64-bit only operating system, no 32-bit support).
2015 - openSUSE Leap
So... my servers are all running openSUSE Leap 42.1 now, and like I said, it's great. Definitely the best server operating system for what I need.
If you manage your own servers (or VPS), and you are ever looking at which operating systems, I'd say check it out: https://www.opensuse.org/
It's nice to have the stability of SUSE Linux Enterprise, with newer kernel/packages, etc.
There are a lot of good articles on it...