General developer forum
Common Cartridge vs IMS Content Packaging
Yes there are differences.
Simply put IMS content packaging standard (IMS CP) defines how to package and describe static educational content.
Common Cartridge uses that same standard to define it's layout and structure but add's some things not present in the IMS CP. That means that if you deal with common cartridge always import it since that is the proper channel for dealing with that format as it will handle everything supported by common cartridge. If you import it as IMS CP than whatever is not defined by that standard will be ignored in Moodle.
Moodle supports import of IMS CC 1.0 and 1.1 and IMS CP 1.2
For details checkhttp://www.imsglobal.org/content/packaging/cpv1p1p2/imscp_bestv1p1p2.html