If you're feeling like an overtaxed and unappreciated serf in Microsoft's kingdom, LibreOffice 4 might just offer the freedom you seek. An extremely capable office suite, LibreOffice 4 is also highly configurable, extensible, and cross-platform. It supports OS X and Linux in addition to all flavors of Windows. It's also freeānot an insignificant attribute for most of us. #Linux
It is sad, tho, that compatibility is seen the other way around. If you want a fair comparison, you shouldn't even bother to see how LO implements OOXML, but how do both implement ODF.