It just came to my mind suddenly: Drupal vs Joomla = LEGO set vs Barbie set.

I will not give you a long and logical explanation here. It's just an allegory. But many developers will probably agree. Drupal is rough and blocky at first sight (but extremely configurable) versus cute out of the box and so predefined (and somewhat messy) Joomla. Or is it just about your way of thinking?