I tried both CMS and I can tell you Drupal is the best, in my opinion. It's easy to try only one and say it's the best! http://blog-money-wiki.com/blog/2007/10/is-drupal-the-best-cms-or-is-it-joomla.php
I typically do all of my sites in joomla. If you are more of a developer drupal is a good one. If you need a cms that has more stuff ready to go then joomla. If you understand templates and css you can create some very different cms sites. www.thestanburyresidences.com www.schroederslater.com are both Joomla these do not contain advertising but they could if they needed to.
After all of this talk about Joomla and Drupal I decided to download and install drupal on one of my servers. Since I'm a php developer, drupal seemed like a good one to try out. It took me all of about 10 mins to install v6. I thought it was very easy. I'm impressed so far with it.