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?
A tribute to my LEGO-ish set of (nostalgic) bricks: it was Deutsche Demokratische Republik made PEBE boxes. Not so advanced as LEGO today and even brickier (and looks quite ugly now). But it was pretty good and available for its space and time.
Thanks to Karlheinz for reminding that it was not PEPE and to Aineias for the picture.
Joomla could be seen as the Lego in this allegory, as all the bricks are predefined and so are most of the parts in joomla, while Drupal could be more compared to a the plastics materials that the lego parts are made of.
Just like windows vs linux.
I'd say very early Drupal versions (and I watch it from v.1) could be compared to plastic in this case. Later versions are more or less complete with functionality and concepts so Drupal not so raw anymore.