As others have said, JTK and GMK both use Cherry profile. Cherry profile can be described as a low-to-medium-height, cylindrical, sculpted profile. DCS and OEM tend to be a medium-height, cylindrical, sculpted profile which is why it feels like there are so many similarities between the sets.
Personally, I find the overall shape of JTK to be a hair sharper or crisper than GMK, but that’s offset by: a) JTK sets often having excess flashing that doesn’t always get completely trimmed off, and b) JTK legends are not as even or as consistent as GMK. On the other hand, JTK sets also run about half the price of GMK so