At Crowd Favorite we use SVN at the core of our team development work. We recently tried to switch from Word and Excel documents to Pages and Numbers documents for estimates and proposals. Unfortunately, we’ve discovered that iWork breaks SVN.
The .numbers and .pages files are 
bundles 
– plain directories that OS X treats differently. Quite reasonably, as a cross-platform solution, SVN does not care a whit about bundles, and treats these as any normal directory and files. The problem appears to be that when saving new versions of these files/bundles, the .svn directories inside these bundles are removed/altered/damaged.
This is clearly a problem with bundles and the iWork apps, not SVN. At least that’s my view – read a counter-argument here.
More reading on the subject, including some work-around scripts: