In most Cortex implementations, you have a very manageable character sheet with any special rules clearly explained on the sheet itself (no need to hunt down Feats or other special definitions during play).

The dice pools do a good job of defining characters and making them unique while allowing a large degree of flexibility. The mechanics and Plot Points tend to ensure that players can almost always accomplish the things they really want to, but it may come at a cost to the character. Personally, I find that Cortex is a wonderful blend of narrative focus and enough randomness and dice mechanics to keep the story unpredictable and the players engaged. As to the strengths and weaknesses of the system, opinions may vary. Combined with your experience with Firefly, that would give a good range of examples before diving into your own. I'd also pick up the free Tales of Xandia quickplay/preview. My recommendation is to read through the basic concepts, then check out the three sample games to get a feel for some of the different ways the system can be implemented.

If you are trying to read it cover to cover, it is going to be confusing.

If you are designing a game, this is wonderful. Every time a concept is introduced, it is quickly followed by a litany of optional rules and other ways that concept can be used. To start with, the Cortex Prime Handbook is awesome in that it is an encyclopedia of the ways one can use and assemble Cortex into the type of game they want to play.

Cortex prime handbook