I just don't think there's comparing isolated ab movements to real, proven exercises. I know a few guys that follow the Westside workouts and all they do in the gym are variations of squats, deads, pullups, and stuff like that and they're strong as shit, as well as ripped. Again, I still do stuff like leg raises, planks, and weighted twists a few times a week, but I feel that I get more from more traditional workouts like squats.
Moving on, I fucking hate front squats! Every time I think I'm making leaps and bounds on squats, I do front squats and get put in check and feel like a bitch. I really need to do them more. I've really been liking the hack squats though. The peaks on my quads have been popping since I've started doing those