Django or Drupal, which one should I use that suits best my needs?
I've built several sites on Drupal and Django, my conclusion is: if you need to create something similar to the standard drupal (or Ubercart) feature-set, you don't have much time for development, and you don't expect hight load pressure on a site - you should pick Drupal.
But if you do need to create something more or less custom (no drupal modules already available) you should go with Django - it is quicker and more pleasurable to implement custom complex features using Django. For example if my goal is to implement a second stackoverflow, I'll prefer Django because it will be extremely complicated to implement this badge-based rating system with Drupal. 
P.S.
Studying Python (and Django) is an investment in your future, I think. You'll never be able to implement something similar to DropBox using drupal and php, although it could be implemented with java - but java is not so good from development speed perspective.
I want to learn and use Drupal or Django for the following: 
dynamic web sites, medium database, multi-level users, paypal integration, content managment, speed (developing), security 
I like MVC, ORM and object-oriented prg.
Which is better to jump into ?  Which one is more mature, powerful, understandable, object-oriented and easier to use by the time ? 
What about Python Spring ...  
Also, which of these 3 are better documented, are better for a cv and have more extensions?
Known languages: php, java, mysql
Thank you !