Drupal classes

So Drupal is notorious for its "learning curve" and the mind-bending endeavor that is 'learning Drupal.'

But is it really THAT hard?

Firstly, this question is difficult to evaluate because so many different kinds of people come to Drupal from so many different levels and types of experience.

You have hardcore experienced PHP developers adopting Drupal for the first time, novices that are deciding to move from Wordpress, complete noobs who heard the word Drupal and became psychotically obsessed with it.