[ActiveDir] Clean install VS Upgrade of Windows 2003

[Bahta, Nathaniel V CTR USAF NASIC/SCNA]

Hey all,   Does anyone have any comments/articles, etc on the benefits or concerns of a clean install of Windows 2003 Server VS an Upgrade?  My opinion is that doing a clean install keeps system root clean.  It also pristinely adopts the security best practices of 2003 Server.  Disk performance will improve as well.  Does anyone have anything they can add to this?  I have migrated a great portion of my network in a clean install path, and now it is coming into question why did I not choose the upgrade path.   Any comments would be greatly appreciated,   Thanks, Nate