When I bought my new laptop, I bit the bullet and also bought Office 2007. I figure that as my clients begin using it, I better know what they are up against.
Office 2007 follows the classic Microsoft paradigm, in that doing simple things has gotten somewhat easier, whereas doing complex things has gotten substantially more difficult. And if you want to customize things, you are in for big trouble. The learning curve is significant, and anyone who is in a position of having to start switching would be well-advised to spend some money on training.
A lifesaver has been the Classic Menu from Addintools This inserts an item called “Menu” in the Ribbon bar, which contains the default toolbars and icons from Office 2003. The beauty of this is that I can learn the new setup at my own pace and if I cam in a hurry to get something out, I can work at my own pace.
In addition, if an office is buying new computers a few at a time, adding in the classic menu means that anyone can use Word, not just the people who have been trained in the new version.