IMO, they all have the same goal. That is, to build a relaxed, connected body that moves from the center and draws strength from the ground, gravity and intent. They all have different methodologies, terminology, exercises and tactical perspectives to get you to build that conditioning into your body and then use/maintain it in motion. One may focus more or less on one aspect or stress one aspect over another at the early levels, but again, I think the similarities outweigh the differences and once you start feeling some of those things in your body that becomes pretty obvious, but the trick is really putting in the time to get that foot in the door so you're feeling these things on your own and not just doing exercises.
i was going to say similar, but since you stated better and i am too lazy to write, so i said "me three". it really comes down to the mixing amount of beans and kimchi. some wants more beans; others, more kimchi. some might want to add cinamon and nutmeg for ki flavoring, but the core ingredients are still the same. incidentiallly, it's lunch time and i got left-over hambone bean soup with 15 different kind of beans. wonder if a side of kimchi goes well with the soup. wonder if i need to be away from anything flamable. wonder if i need to be outdoor. wish me luck!
ps. folks who have no understanding of ki, has no understanding of IS/IP, nor do they understand the value of aiiieeeki.