I recently rolled my 1020 back from the 8.1 preview to 8.0 - I found this thread today and thought the information I'd posted already elsewhere might be useful to anyone else considering doing the same.
Most of this seems obvious in hindsight, but I wish I'd known (ie. thought through properly!) all of these things before I started:
1. the sms / settings / photo and video backup built into the phone doesn't work as you'd expect. Back up your documents / music / photos and video's somewhere you can find them manually - ideally a PC rather than onedrive for speed reasons. I made sure my phone system backups were upto date as well as making local copies. Then found that the backup doesn't restore to a rebuilt phone (or if you were to upgrade / replace your Windows phone with another Windows phone) it seems only to restore to the same phone with the same software build. This said my old SMS messages reappeared a day later, but not the photos, videos, apps or music.
2. reinstalling and re-entering all my account credentials / preferences / rss feeds links / podcast sources etc in the different apps was REALLY tedious
3. don't be too precious about remembering how you had your home screen - until 8.1 rolls out to consumers (that should be very soon) you can't hope to put it back as it was because Win 8.0 only allows two large tiles or 4 smaller ones in a row.
4. Reinstalling apps after your phone has been restored to 8.0 isn't as straightforward as similar resets on Android. Navigating direct to the App Store on the phone looked as if all my purchase history had been wiped out - apps I knew I'd paid for under the same Microsoft account were showing with a purchase price. However going to the app store via a desktop browser, showed my full purchase history, and allowed me to select all the apps I wanted to reinstall and "push" them down to the phone.
5. Map downloads for the Here apps need to be downloaded again - as they're around 450MB each you might want to make sure you're on WiFi and have a well charged battery.
6. It probably seems obvious to everyone else, but as well as re-entering all your WiFi networks, you also have to reset your Bluetooth connections, I only realised this as I got in the car to go to work and tried to answer a call through the hands free thing
Hope this helps someone.
Jim