No, the client is not supported and yes it works with most of the features. In my case I used Jason Sandy’s startup script to get my client installed. Here is a few screenshots of what I have tested so far:
Client is installed and assigned
The Application Catalog feature works
Application and package deployment works like a charm
Compliance Settings tested and working
Inventory works
Software Update scanning works
OS deployment works – just check the blog post from Johan Arwidmark – http://www.deploymentresearch.com/Research/tabid/62/EntryId/192/Beyond-unsupported-Deploying-Windows-Technical-Preview-with-MDT-2013.aspx
I tried installing the SCCM 2012 R2 client (as of CU4) onto a Windows 10 machine (ccmsetup from command line) and received nothing. No errors, no logs, nothing. It simply didn’t install. Are special command-line switches (in addition to the usual ones) needed in order to install the client on Windows 10?