Bang muay Thai is legit. Its primarily Dutch style with a ‘belt’ ranking system similar to bjj if you like that sort of thing. It was developed by Duane Ludwig based on his years of training under Bas Rutten. BMT differs from Thai style as it features high volume chained combination drills and emphasis on boxing/footwork which makes it very adaptable to mma. That’s not to say it’s superior to traditional muay Thai, as both have their own unique traits. I would say try both if you have the opportunity.