Data Loss While Upgrading to V04?

I heard form many people on the forum that the update is nothing to be excited about, I'd like some reassurance. But my initial question is that 'does doing a firmware upgrade have a high potential in data loss, i.e. pictures, videos, notes, and so on?'   I heard from a Verizon rep that there may be a  chance that that will happen during the process.  If that is the case would it be a good Idea to back it up in Bitpim, then do the upgrade myself, then reinstall the backed up data?  By doing that would that interfere with the upgraded firmware when reinstalling the data from V03?

Thanks a bunch in advanced

Thank you for your helpful information!