Just upgraded the Gitlab installation at work. Was fairly straightforward once I ran into the upgrade docs shown here: https://github.com/gitlabhq/gitlabhq/wiki . Feel free to get in touch if you need help setting an instance up for your team.
Recently I installed CentOS using a USB Stick on my laptop, and blogged about it.
I am currently using CentOS, and it is a fairly good experience, although I am still not able to connect with wireless, although it is almost set up correctly (I even had it going for an hour or so, then rebooted 🙂
Anyway, I am glad for the opportunity to learn to use the RedHat set of administration tools, and switch distros for a bit.