See What's New in Windows Server Technical Preview
I like the new features in Hyper-V, the new Server Antimalware feature, and big additions and changes to Storage Spaces.
I run all my servers now as virtual machines. The only thing I have native on the hardware is the Hyper-V role. Facilitating failover and supportability of these virtual machines is going to be the highlight of the new server.
I wasn't clear, sorry about that. I didn't mean to disparage the 2016 TR, in fact I'm pretty excited about it.
[Rant]
I was disparaging 2012R2 for the fact that it looks/feels like a Fisher-Price toy because of the UI they picked for it. I don't have time in my job to be playing with themes, I have too many machines to manage, so I use the default UI by necessity. I find it annoying and it wastes my time finding things and shuffling around in a theme that looks more like Win3.11 than I care to describe. So I look forward to 2016 as a return to a server that looks and feels like a server, not a 2005 cell phone.
[End_rant]
I plan to spend some time with the MS Hypervisor -- to date I've used VMware ESX/ESXi extensively and Xen moderately, and I find them both great. I expect that Microsoft has done a good job with their virtualization.