Pages and Numbers are much easier to use, and far nicer to look at than Office. If I don't need the horsepower I prefer iWork. If I do need the horsepower I have Office 2003 running on a late 2009 mini that is Windows 7 only. Office 2003 works great with W7, and it's not all blue looking like some of the newer versions.
As usual Windows runs MS software much better than Mac OS does.
They made Mac OS office very similar to the windows counterpart in the 2011 version. Granted its not 100% the same but the gap between office 2011 on mac and office 2011 on windows is very tiny now.