If you've created any Publishing sites (WCM sites) in MOSS 2007 Beta 2, you need to be aware of something. There is a known issue that after you upgrade to B2TR, your Publishing Sites won't work. Here's the issue you'll see when browsing your site:
An error occurred during the processing of /_catalogs/masterpage/TopNavFlyouts.master. Type "Microsoft.SharePoint.Publishing.Navigation.PortalSiteMapDataSource' does not have a public property named 'TrimNonCurrentHeadings'.
The easy fix (if you've just been playing around with WCM), is to delete your site and recreate it.
However, some customers have obviously been actively building real sites... and deleting their work just isn't an option. For these people, a workaround is coming, which you'll have to do to get your B2 sites to work in B2TR.
A workaround will be available very soon... I'll make sure to post it once its available. I wanted to get this out before those who have created WCM sites in B2 that can't be deleted tried to upgrade to B2TR and freaked out.
[Added 9/15 @ 2a] Here's the fix for the issue mentioned above: MOSS 2007 Beta 2 WCM/Publishing sites break when upgrading to Beta 2 Technical Refresh... and a fix!