Drupal: will drive you mad, but SOOO powerful! Almost anything can be achieved in Drupal: it'll take ages and sometimes it would be quicker to simply write what you want from scratch - but still, its power and flexibility is pretty remarkable. Keep away from the civicrm implementation and all will be well - eventually.
Joomla : Don't. Just, don't. OK, there's a lot of documentation and it's very configurable but it's written for idiots so finding the info you want is really hard as it floats in a sea of fluff. The userbase are full of myth and misinformation, and the code's horrible. Not Drupal, stretch your brain kind of horrible, more 'why would they DO this' horrible.
I can see why it's popular with graphic designers because you can dump the whole template into Dreamweaver, but that's not necessarily a good thing.