i just watched a bunch of their videos, some of their certification sessions, looks tough, but a fun way to push yourself and maintain overall fitness. I'd like to try something like that.
Here is the deal on crossfit(SF guys are all over this right now). It really builds core strenght, everything is based on building that. Lots of pull ups/squats and it isn't designed to be a full work out. You have to do other things if you want size or really get in shape but it is an awesome work out supplement to rip you up and get you in shape. Most guys I work with don't do the work out of the day but are like a week behind so if they miss a day of not having the net it is no problem. The best part is the hot chicks that are in way better condition then anyone on EF.
it incorporates olympic, gymnastics and bodyweight stuff. so if u want to do crossfit style shit base your routine around pullups, dips, squats, deadlifts, cleans, kettleballs and tires.