Here are some examples of the sites and some of their statistics:
http://www.pssatraining.com this site has 177,000+ members taking approximately 4,000 saves of modules per day.
http://safeyouth.hbgdiocese.org this site is a multi language site delivering training to approximately 6,000 members.
http://www.imclearn.com this site is a private site only open to truck drivers that have been approved by the client, but it has 20+ modules available for each member with enrollment, surveys, and aggregated reporting.
http://online-training.penntrain.net this site has over 100 modules available through enrollment to 2,000 members, and it has pre-requisite rules associated to many of the module.
Nogle has a typical LMS hierarchy that umbraco handles perfectly with Program / Curriculum / Course / Module available. Individual certificates per level are available along with rules such as enrollment by member or member-role, pre-requisite. It also has event notifications such as module-passed, module-completed, etc that allows notification emails to be sent.
We're pretty happy with the product that we've been developing and using for 2 years, and I'd be happy to chat with you if needed.