My only thing with Crossfit is that they allow weekend warriors and beginners to do it when they have no business doing those types of workouts. There are videos on youtube that make me want to call an ambulance for the poor people.
Someone who hits the gym regularly, has a good solid structure and knows how to lift and move their body properly, no problem. But when you throw a kettlebell at Wally Weekend and have him suddenly do 100 reps until he dies it's just not a good thing IMO.