920 from 8.1 to 10581, hard reset. Downloaded 10586 on my 920, got the expected reboot loop, did the power/volume hard reset combo, restored from backup, apps are still downloading. Regarding the 10581 hard reset bug, WMPowerUser claimed the hard reset combo may not actually work and may send it into a worse reboot loop and/or brick the device, and they recommend going back to 8.1, then going to 10586. I did not have this issue, but just thought I'd share in case someone else had the issue.
Edit: FWIW, it appears that Lumia and HERE branded apps are not downloadable in 10586.
Edit 2: MetroMail crashes before it can start, but Glance works now, as does setting special sounds for texts and emails.