The WTF tae-kwon do its more for tournaments. Fast points, easy to hide kicks and a lot of movement.
ITF goes more for "street fight" kinda style, but still keeps a lot from tournaments. They dont use too much the hands, but they teach you to fight with your elbows and complete body at the same time you use your legs with the same technics that WTF, with a few little details for short kicks situation with full potential
ITF its amazing for tournaments since it teach you to do amazing kicks when you are really close to your opponent and they have a lot of power, but they are really slow compared to WTF who search for a quick connection between the leg and the opponent for a easy tournament point
Just in case. Sorry for the shitty english.
I think if somebody its interested about this I could share it because I was a fighting in the nationals in Argentina and idk, the difference between both its really huge when you train them for a long period of time