Office 2007 and Mac incompatibility

News.com has the scoop here:

New Office file format could cause headaches

This makes me wonder, if OpenOffice (or its Mac cousin, NeoOffice) would have an easier time at opening the new file formats & types than the Mac or Windows's previous version of Office. I've been using NeoOffice exclusively since switching over to the Mac. I've never personally required any of the advanced capabilities of Microsoft Office anyway.

As much as Microsoft champion the idea of backward compatibility (after all, that's why it took so long to get us from Windows 3.1 to Windows XP, right?), it's surprising to me that they would devise a format that causes so much backward compatibility issues.