i feel like i have had an exceptional learning experience b/c I am learning boxing and kickboxing/thai boxing along with TKD (knees, elbows, spinning, turning and aerial kicks) and spar regularly (when i'm not hurt). this gives me a better understanding of distance control, tiring out an opponent who's bigger than me, jamming an opponent to conserve energy, not telegraphing my punches etc. Not all dojangs have such a well-rounded curriculum, obviously. I was just fortunate to find a teacher who had backgrounds in TKD, boxing, grappling and had studied other arts as well, including kune tao.
I have been rehabbing a broken ankle for the past 9 weeks and when I come back from TKD, I have more flexibility, less pain and greater mobility in the ankle.