Metabolic conditioning seems (to me, I could be very wrong here) like one of the most ignored components in a lot of traceurs' training programs. We tend to favor skill work and plyometrics highly (naturally

) and even focus a lot of muscular endurance, maybe some cardiovascular endurance, and strength/power.
The culmination of both muscular and CV endurance with a fair str/pwr component is what makes metcon metcon. If your max amount of pushups is 30, doing 25-30 pushups is going to be HARD and probably hurt a lot (uncomfortability, not actual pain).
But switching from doing 15-20 pushups for time, grabbing a dumbell and doing pistols for time, then grabbing a bar and pressing it over your head for time all without stopping in between is REALLY DAMN HARD, but also quite useful to achieve functional movement endurance [of course assuming your'e doing functional movements], with potential for strength gains and power translation.
I personally favor power/oly lifting based metcons, perhaps with some skill-specific movments in there, usually against the clock. But, like ANY program, focus MUST be on form first, output second. And I think it goes without saying that you can overtrain on ANY program, due to poor intake and not really giving yourself true rest.
I could get rhabdomyolysis from crossfit, a broken ankle from parkour, a torn disc from mma, ITband syndrome from lifting, or shin splints from running.
At the same time, I could get none of the above from any of the above.
All in all the fundamentals of a long-lasting effective program will stay the same. Form, recovery, progressive overload. The specifics of the program are what bring about the change you want.
Hopefully, and is oftentimes not the case, the program an individual chooses is accurate to the results they want to realize.
Finally, as a note to the readers as well as the contributors, I'm limitlessly glad we have the community we have here. The huge base of knowledge, the mature discussion, and willingness to assimilate or even accomodate. You guys truly are awesome. :]
ps: Yes, Andrew. You made a GREAT choice. Read, digest, and utilize all of the information in that wonderful little book.