Warning: Lumia 920 'Bricked'
A simple word of warning, attempting to do a reset (back to factory settings) on your windows phone is likely to render it useless.
I had been using my Lumia 920 for around a month and I wanted to totally wipe my phone to factory settings so I went into the system menu > about and then chose to reset my phone.
Bad idea...I got the usual gears turning logo for about 45 minutes and then nothing. Attempting to switch on the phone only got as far as showing the Nokia logo.
I assume the WP8 OS is not as robust I would like to think it is and basically corrupted the OS and was unable to perform a simple roll-back to factory settings.
Funny thing is I did manage to do a successful rest when my phone was about 1 week old when I had relatively only 2-3 apps on my phone and not customised or used it heavily. So it seems that the longer you use the phone and the more you apps and customisations you do to it the more likely it is that the OS will be unable cope with a factory setting reset/rollback.
I live in the UK and after a lot of waiting in store and a few phone calls luckily Phones4U decided to give me brand new handset out of good will even though their normal policy is to send it back and get it repaired if you bought the device online.
So there you have it, WP8 is not robust and I think Microsoft need to give the users the ability to download the firmware OS and install it themselves via the WP8 Desktop App, similar to itunes and iphone.
I am also hoping that the Store app push updates start working on my new handset as old phone would not notify me of new app updates. Fingers crossed when we get the Portico update in the UK it does not brick my phone...