Does Buddhism claim perfection?
That's a ridiculous statement.  How could you follow something sincerely that wasn't built on solid ground?  If the dharma wasn't certain, pursuing it would be a complete waste of time.  While it might not answer larger, existential questions like "why are we here", it is a fairly reliable point of departure.  

Uncertainty is, however, a very important part of practice.  In fact, doubt and frustration are one of the most salient features of the path.  Buddhism doesn't seek to give answers.  Instead it asks us to reevaluate our assumptions.  It's very aim is to disrupt the order we've conjured around ourselves. 

I wouldn't go so far as to say that Buddhism tries to perfectly describe the nature of the world.  The very act of describing it inevitably reduces it to ideas and descriptions.  What Buddhism does attempt to do is give us an opportunity to see the nature of the world perfectly.