I don't really see the difference between the two other than for pulldowns, it's easier to increase the resistance and you can vary the shoulder angle by leaning back. I disagree with whoever said that a pull-up is more natural... for either exercise, your hands are at a fixed position throughout the movement. See this here:
The only way I would consider one 'more natural' over the other is if your hands and arms were able to move independently... The only way I can think to do this for a movement similar to pull-ups or pull-downs is to hang upside down and use free weights in basically an upside-down shoulder press, which by the way, I would NOT recommend
Oh and I definitely think that pull-ups look more impressive... mostly because most people don't do pull-downs correctly![]()
You might want to explain your comment better. Cause as a Kinesiologist and a cert'ed ACSM... You should know know the difference between the two and easily explain better than "I don't really see the difference".