I went with 2012 RE2 because of lots of issues with raid cards under Win 10 and wanted something else to try - 2016 is a tad to shinny and new - and usually that means some issue with it being MS - and had six weeks of faffing around did not fancy anymore
Also if you look on ebay you can find Essentials 2012 for as low as £20 for the lic number - i got my first one at £80 and downloaded the technet preview version and installed and activated no problem
First impression is its stable and finds most things out of the gate with working drivers - what i dont like is the interface (part Win 8) and the way it forces you to the dashboard and makes finding some tools kind of difficult - i.e. several clicks to find computer management - to get to disk management - to map a drive. could be i have not found it in the dashboard but.....
Overall its a server version of windows and it will do what i need once i get used to the interface or change it so its more Win7 ish rather than win 8
If you do go Win 2016 - comeback and start a thread so we can see if you find it any better - not looked in detail but i did not see a huge feature set change?
DrivePool & Scanner on 2012R2 Essentials Server Gigabyte Z87x OC Force, i7-4790S, 32 GB, LSI 9211, HP SAS Expander, 27 Storage disks, 6 SSD Cache, ~115 TB Storage