Hi, Trimble.
The main difference is that the retail package will not die anytime soon.
To quote from KB 971767:
"Effective June 1, 2010, Windows 7 RC will expire.
"To continue using your computer, you should prepare to install the retail
release version of Windows 7 or install an earlier version of Windows before
the June 1, 2010 expiration date. You will be unable to upgrade from Windows
7 RC to the retail release version of Windows 7. However, you can back up or
transfer your data to your next or previous operating system."
There are several phases in the expiration process, including:
"Effective March 1, 2010, Windows 7 RC enters the next phase of expiration:
"Expiration notifications in the task bar continue.
"Computers that are running Windows 7 RC restart every two hours.
"Important When the computer restarts, your work will not be saved."
For details, read the KB:
Description of Windows 7 Beta and Windows 7 Release Candidate (RC)
expiration dates and functionality
http://support.microsoft.com/kb/971767
Your Subject asks about differences between RC and Retail, but your text
asks about differences between Professional and Ultimate. The same
expiration phases apply to all RC versions.
RC
--
R. C. White, CPA
San Marcos, TX
(e-mail address removed)
Microsoft Windows MVP
Windows Live Mail 2009 (14.0.8089.0726) in Win7 Ultimate x64