10586 works awesome on my brothers Ativ S. I did flash new FW grozaman posted. I think performance may even be better than on my Lumia 735, except locckscreen sometime shows 2-3 seconds later which isn't present on Lumia.
Had some trouble with APN, didn't wanted to work, changing, editing, switching to auto, and somehow it started working suddenly, have no idea how
Also, after hard reset after upgrade on introduction screens there was flickering on display and couldn't find WiFi networks, but after simple restart it came back to normal.
Overall, it works really nice, much better than expected.