So, with Jake Mace there is a lot of controversy about his training, mostly due to his teacher being labled a charlatan with no proper lineage in any Chinese Martial Art. Jake has a similar reputation and gains a lot of hate from the CMA community, particularly when he demonstrates his Taijiquan and Baguazhang techniques. Now, it's up to you whether you believe in the controversy or not, and whether you believe he actually was trained in the styles he claims he was, or if he just learned them himself. I honestly couldn't care if his CMA is "authentic" or not, my problem with him is in his self-defence videos. In short, he advices using techniques that are very risky and require a great deal of strength and skill that your average person wouldn't have, making them very dangerous to use.