I'm just a pilot and not a hyrodynamic engineer so I'll try my best.
The reason landing is longer is because you have no idea how high
above the water you are. So you try to cross over the shore around
5-10 feet and then just set up a slow decent until you feel the slash.
That tends to take up more space since you're waitng for the water.

The take off is longer because the floats stick to the water. I'm not
sure how to better explain it but you can certainly feel it. When the
water is choppy the floats come right off the water but when its
smooth you can actually feel the water pulling on the floats as they
try to pull away. Once the floats break free of the smooth water its
feels like you just got released and you feel a noticable speed
increase in ground affect.

-robert

Very interesting. Thanks for taking the time to explain it to me.

Now I just wonder why the floats would stick?!?! I am going to have
to find something that I can read about this.

Man would I love to try that sometime... That has got to be one of the
coolest things ever!