I havent got The System, but from what i have seen of it, it is actually more involved than The Trilogy, in the sense that most of the material is all of the same level.
The Trilogy has a section on the third disk called Flourishes 101, which teaches all the basics you need, from the revolution and charlier to the fans, shuffles and all sorts of stuff. The level of variety of flourishes on the 2nd disk all range between beginner-ish to advanced, but you will accomplish any of them if you put enough time in. As i said before, i started 3 months ago and have already learnt the jackson 5, so if you put your mind to it anything is possible.
I cant comment on Motion yet as i am waiting for it to come in the post, however by what i have heard and seen, it has better presentation than the Trilogy, however i don't know whether it has as much of a range of stuff as The Trilogy.