I feel like for most users, it's easiest to just press Restore in iTunes.
It will automatically fetch and download the proper IPSW.
A lot of "faulty" restores may be due to forum members not being sure as to which to download.
I'd rather have control over what i install, also going that way means a lot of people will hit update instead of restore, a clean install is better, that is also what PB is testing the JB on, chances are that remenants of the old furmware or OTA remain that way.