There are many content management system (CMS) solutions available across the web. Choosing the right one that fits someone's needs is a difficult thing to do. Just take a look at this overwhelming list that Bob Doyle put together. He has compiled well over 2000 solutions.
Every Module that I have downloaded so far from the official Drupal.org website has had major issues. The majority of what I have seen has been Browser compatibility issues. If the themes will be listed on the drupal site then shouldn't they be pass some set of standards?
Steve Yelvington has a good article here: http://www.yelvington.com/why-do-drupal-themes-suck
Conclusion: One must take the time to design personalized themes and not rely upon the official repository.