I've been thinking about using W10 as my server recently. MS has pretty much killed the home server market via pricing and poor support like the issue you ran into. Essentials is an after thought for MS.
The one thing that keeps me from moving to W10 is the remote access piece, but since that is not a requirement for you, I'd suggest W10.
I posted this in the wrong place. It should have been in the WHS 2011 > Lights-Out section where there is already a discussion about LO problems with the Windows 10 feature update:
After the latest Windows 10 Pro update (version 1607), my PC no longer wakes up the WHS 2011 via Lights-Out (18.104.22.1688) on boot. It does not keep the server running either.
The Lights-Out tab on the WHS 2011 dashboard shows that the PC is off. However, the Lights-Out client on the Windows 10 PC shows that the server is running.
Anyone knows how to fix/work around this issue? Thanks.