Veterans of Office 20 for Windows will feel most comfortable with it, but unlike those versions of Office the traditional Mac menus are still available as an alternative.
The Ribbon takes some getting used to as it's unlike the interface of any other Mac program, but it's worth bearing with as it generally is easier to use than the interfaces of previous versions of Word. For example, inserting an Excel chart or a photo automatically switches to the Charts tab or the Format Picture tab respectively. It automatically switches to the tab with the most relevant commands depending on what you're doing. This tabbed toolbar makes Word's numerous commands and options easier to discover, compared to the numerous individual toolbars and palettes of previous versions. Like the other Office applications as well as Office 20 on Windows, Word 2011 has the new Ribbon interface. The most noticeable change is the new interface. One would be forgiven for thinking that there's little that can be done to improve a word processor that's been around since 1985, but Word 2011 has been markedly improved over previous versions.