Cinema 4D is usually used to make the motion tracking for the montage, sort of an intro into the montage itself, and sometimes the actual user's introduction itself. For proper motion tracking, it would help to have the program Boujou as well. Most editors either use Adobe After Effects or Sony Vegas Pro (I use Sony Vegas Pro 11) for the montage itself.
As for Cinema 4D, it's not a free program. It's rather expensive, but I got my copy for free with my special ways (You can probably guess how, hah). It's not really easy to use, or hard to use. It's just about going through the program and learning how to do what, which tutorials can easily help with.