It was answered. Win 10 storage spaces supports everything the Server version does - but there's no GUI, it needs to be configured via Powershell. Quoting from an above post (that is itself quoting from a reddit post)...
Was playing around with 10565 and noticed that storage spaces has been vastly improved. The most noticeable is the control panel now has options to rebalance drives as well as a way to prep a drive for removal. Very nice. But under the hood
I've also discovered that it now supports all the server 2012 R2 features - tiering, write back cache, etc. The only thing is that without a GUI, you need to configure it with powershell. But it works perfectly once you do. Hopefully they'll have a decent
GUI for this soon, probably why they didn't announce it. Hopefully de-duplication and an improved ReFS are coming down from server in due time, but SS is finally good enough for everyday use.