My customer's new MOSS production environment has been upgraded from SPS 2003 and went live this morning, yes!
Some minor issues remain though.
Here's one SSP issue I just fixed temporarily.
I went to the SSP Admin site, clicked on Search Usage Report under Search section, then I was prompted for credentials. I tried putting in all kinds of accounts including the SSP app pool account but nothing worked. Eventually it errored out with 401.1 access denied page.
When I looked at the Event Log in the Central Admin server, I saw the following error:
Event Type: Error
Event Source: .NET Runtime Event
Event ID: 1023
Time: 10:01:42 AM
Description: .NET Runtime version 2.0.50727.42 - Fatal Execution Engine Error (7A05E2B3) (80131506)
For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
I looked it up and seems like this is a bug in .NET 2.0 and there's a HotFix for it.
The error occurs when there's a no user profile associated with the application user account context.
So the official solution would be obtaining the hotfix and see if that fixes the problem. In the meantime I just worked around the problem by adding the SSP account to the local admin group on the Central Admin server. Right now if I login to the SSP admin using the correct SSP account and then click on Search Usage Report link under Search, I can see the Search Queries Report.