I used to have to spar with black belts in Chun Kuk Do from the Presti Karate School in Niagara Falls about once a week back in my fighting days. They used to come to the gym where I trained to learn full contact sparring & they were all tough guys. Their instructor, John Presti was a student of Pat Johnson ( who choreographed all the KARATE KID movies & the COBRA KAI series as well ) & Chuck Norris. I believe he's a 9th Degree black belt in Chun Kuk Do. So, his students are all highly skilled. From what I've heard, Presti is tough as hell on grading & it takes an average of seven years to earn a black belt from him. So, his students are very good fighters & martial artists.
They couldn't box at all though & they took their lumps in sparring. But none of them quit. I caught one with a left hook once & split his eye open which needed 12 stitches to close but he showed up to train the next day to train. So, I was impressed. Knock 'em down or bust 'em up, they always came back for more. That impressed me. So, my trainer & I worked with them when we could & a couple of them really caught on & improved a lot.
They were much better at kickboxing in the beginning though. Each one of them had great kicks from Chun Kuk Do's Tang Soo Do base & if I let my guard down they tried to take my head off. One of them caught my training partner, Ken Graziano ( who was a world-rated PKA kickboxer ) with a spinning back kick to the ribs once & dropped him. And Kenny was very difficult to hurt. So, yeah, they could kick like mules.
They eventually stopped coming to our gym after about six months though. I heard Presti put an end to it because they were spending more time training with us than they were with him & he didn't appreciate it. But it was fun while it lasted. They taught me a few things that I didn't know as far as joint locks, chokes & throws were concerned in return for my time helping them & sparring with them so that was cool.
So, yeah, Chun Kuk Do is very legit & in my experience, its representatives are excellent martial artists & gentlemen.
Do you train in Chun Kuk Do?