Really If you become a legitimate tkd fighter you will be pretty good however you have to find the right school alot of tkd schools arnt that good and won't serve you well in a fight.
MT schools are almost always legit and you learn more punches.
they are just good for different things tkd is good with kicks and forms and mussle memory
while MT will teach you better boxing skills and clinch work.
they both serve as great base styles just look at prices location and the experience you cant go wrong with either.