If you want something that's approved for production use, then you should use Server 2012 R2 with all patches installed (including KB3000850). This includes the "DSC 1.5" changes which make it quite a bit easier to use, and forward-compatible with configurations authored / compiled on systems with PowerShell 5.0.
If you're feeling frisky, you could still use Server 2012 R2, but install the latest version of the WMF 5.0 Preview instead. This is pre-production software and you may encounter bugs, but DSC functionality is _much_ improved by new features such as support for class-based resources (much nicer authoring experience), better integration with third-party tools (Chef and Ansible can already take advantage of the new Invoke-DscResource command, and I think Puppet might be there as well), the ability to debug resources as they're being executed by the LCM, and so on. WMF 5.0 will be officially released along with Windows 10, I think, some time this summer.
Thanks for the reply Dave, I think I feel frisky haha I'm only testing this as a proof of concept to present to my current manager so they can maybe use it when they spin up a loads of new server with with a new system they will start to use soon.
I'll share my queries as I go along.
I still need a convincing argument to get my manager to move to Windows 8.1 but that's a topic for another day haha
But any other recommendations or things to watch out for would be appreciated.