Which open source eCommerce solution is the best?

Which is a better eCommerce option?

– Drupal + Uber Cart
– osCommerce
– Magento

Magento is a (pardon my lingo) kick-ass ecommerce package.  It has so many functionalities that its amazing.  It is still evolving though.  Some people, though, have a need to combine a CMS with a cart – so the obvious choice with Magento is Drupal.  Although there is some discussion on integration of Magento with Drupal, it is still considered to be tough.  Uber Cart, meanwhile is easily integrated.

Uber Cart meanwhile has been tried and tested in Drupal.

As for osCommerce, it has been the defacto leader in the open source arena for the ecommerce.  However, one – it might lose that crown to Magento and second there is a conclusion that Drupal is more flexible and better than osCommerce.  Some discussion.

So, if you start to build your cart, where should you start with?