I don't understand the fuss, it is minimized by default and works well on a touch screen by showing a lot of common commands. It's like people love to hate it or something, especially ones that don't even use Windows daily.
But Office on the PC wasn't made for a tablet - they intended the ribbon to be used by PC users, and it's terrible. Removing the menus eliminates discover-ability. The common case now when using a recent ribbon-enabled Office application, for me at least, is vaguely recalling a function that I used in a previous version and then hunting around for 2 or 3 minutes through the UI and not finding it. Without doing google searches, I'd never be able to find these features. And each of these feature-hunts adds up to a lot of wasted time.
The ribbon is a massive, massive step up in usability, the difference is you already knew how to get to features in the old version, so there was a learning curve. Show two people who are brand new to office Office XP vs Office 2010, and I an completely certain that they'll have an easier time with 2010 (especially Excel, the usability difference there is incredible).
Sure, if you use the "more frequently used options" but try using something a bit more obscure and you are out of luck.
At least with the menu system you had those "breadcrumbs" to give you an idea of where it could be.
If you're trying to do anything other than the obvious stuff, then yes. I struggle to find anything in Office w/ Ribbon, whereas I could almost always find what I was looking for in a few seconds worth of menu hunting before. Personally, I find discoverability to be absolute shyte with the Ribbon interface.
But, I only use Windows at my dayjob where I have no choice, and I try to spend as little time as possible paying attention to the fact that it's Windows (hello, Cygwin). I'm probably not exactly the target market for MS on this to begin with. ;-)