Ultimately, this is a modern FOG, so I’d recommend a modern OS level for 0.33.
It really doesn’t matter which OS, though I’ve really only tested thoroughly on CentOS as that’s what I run at home. I’ve performed a few installs on Ubuntu and Debian so far, and others have done so on Mageaia (or however it’s spelled). It seems to work well from what I have seen, on all systems.