There will always be a couple of people that either really do have a problem or perceive to have one when it does not exist. Obviously, the ones you quoted are very unhappy and will not allow themselves to have any joy because of it.
I don't know for a fact if the Santa Fe uses the same transmission as the Sonata, but it may be. I have a Sonata Limited with the five speed. When I pull out of my driveway I make a turn to go up a hill. On a cold winter day, the first shift from 1 to 2 is a little slow. After that it is fine and the rest of the shifting is positive and smooth. I don't notice it in warm weather.