Just one so far and only as a file server but that was just a matter of entering my normal workgroup ID.I have WHS 2011 just now and it's fine but W10 no likey so I thought it might be time to move on. It's mainly for backup and the access away from home has been used now and again but not a biggie.
I've seen 2016 but think it's deffo an overkill for me, in fact 2012 essentials is possibly an overkill
@Snapsh0t do you have W10 pc's using WHS 2011?