Why did we leave Mambo and are now using Drupal CMS? ...ok, you maybe want to read more...
Now, when making any comparison such as this, the first thing to realize is that it’s unlikely that one tool will fit every need and purpose. To an extent, comparing Mambo and Drupal is comparing apples to oranges. They are two very different systems, with widely differing goals and intended audiences. They just both happen to fit under the convenient heading of “content management systems”, meaning you can create decent websites with either one of them.
Also, the people on our team probably don’t represent the broad cross-section of Mambo users out there; our needs don’t necessarily fit their needs. We are. for the most part, people with strong technical backgrounds. Some of our reasons for abandoning Mambo may not resonate at all with the “average user”, if there is such a person. Unless you are a programmer, or have an equally deep technical understanding, take everything we say with a grain of salt...