

I find I much prefer Moodle to the leading commercial system I use in my day job. (that is one of the links on the Moodle Buzz page that Marting mentioned) You can see a good comparison of ATutor and Moodle at I found the user interface of Moodle much, much easier to understand than ATutor. The ATutor folks make a great play (reasonably so) of their accessibility and standards complience such as IMS, SCORM and WC3 WCAG, though moodle is no slouch on accessibility either. I looked at ATutor after Moodle and I was impressed, but Moodle has a very significant edge in functionality. That and some other niggles put it out of the running for me.

If you are fluent in French it is a contender.

#ATUTOR SOFTWARE CODE#
For me Claroline suffers from its Francophone origins in that the code comments are in French. I have looked at 3 of what I consider realistic Free/Libre options for this type of software. Perhaps you are casting your net wider than I was in terms of functionality. Wel Seb if you have found hundreds of high grade GPL options in this sector I'd like to see a few links.
