It's a great idea to have just the one platform across all devices, and MS took a while to get there, what with non-cooperation across the different developmental divisions, but at least they got there. I just wish that MS wasn't being so aggressive in pushing Win 10 out there, by forcing unsure or unwilling users to adopt it before they are ready or willing to.
Having said that, Windows 10 does have advantages and improvements over previous iterations, and it will likely get better over time. Hopefully the compulsory update issue is resolved so that users aren't faced with forced updates that can break their systems, or parts thereof.
At this time I still prefer Windows 8.1 over Win 10, largely now because of the compulsory updates, but it seems likely that Win 8.1 will become less viable over time, and that acceptance of Win 10 is inevitable if one wishes to remain with the Windows platform.
As for Win 10 on the phone, my current handset isn't eligible and I see no reason to upgrade to a newer model when this one works perfectly well. However, when the time comes to buy a new one, it will be a Win 10 phone as I do not like Android or IOS