I mistakenly ordered a laptop with Vista and the new Microsoft Office installed. Both present a new user environment. I am a power user with Excel, and found it very difficult to use the new Excel. They replaced all of the menus with icon panels, with beautifully redrawn icons, and scrambled the locations up. I'm playing a game of guessing what the icon does, hovering, and reading the "tool tip" to be sure. Talk about an "unfamiliar environemnt".
My entreprenurial landlord teaches classes for small businesses on how to switch to Open Office instead of the new Microsoft Office. If they're going to have to retrain anyway, why not go to something that is free?
(Alternatively, it could just be that I am getting "old". When I was a teenager I shifted from WordPerfect to Emacs with less difficulty.)