Although Chris Pirillo has composed a list of items that still need work, the first few hours with build 5384 have been pretty good. The install went very smooth. Even the smaller changes, make the process of installing a new OS more pleasant. For example: after selecting the locale, setup choose the right keyboard layout.
Limiting the privileges of the user (LUA) does lead to some small annoyances. Even when the user-account belongs to the local admin-group, accessing the local SQL Server from the Visual Studio enviroment doesn't work. For some reason the Sql Server Management Studio does manage to get access to the database. It turns out that after adding the specific user to the sysadmin-role on the database, the problem disappears. Minor discomfort.
The package in the SSIS-project I moved over from my XP-machine, initially failed to run. The (unchanged) package produced the following error: "the thread for the SSIS Bulk Insert task failed initialization". This happened at the point where data was being copied to a SQL Server database. Changing the destination from "SQL Server destination" to "Ole Db destination" seemed to resolve the issue. After changing the SQL datasource from integrated to SQL-login, the errors went away entirely. Because I'm not able to reproduce the initial error, i am not a 100% sure about what caused this. Might not be related to Vista at all.
On Vista-based machines it is not possible to send new messages using Outlook Web Access. Applying the fix at http://support.microsoft.com/kb/911829 should solve this. According to the knowledge base, Vista doesn't support the ActiveX control that is used for HTML editing.
Besides from these minor issues the experience is very good: I haven't seen any errors; all of the hardware was detected automatically. Even after installing Office, SQL Server and VS, the performance isn't any different from what I had running XP. From what I've seen sofar, they should be able to ship before the end of the year.