My Local Gun Shop had a 20 and a 20SF.
My hands are fairly slim, with slightly long fingers (I wear a size 10 glove), and I usually don't mind a thick grip, like the HK Mark 23 or the old S&W revolver grips.
But when I held the 20 and 20SF, my fingers wrapped around the 20SF slightly more and my finger joints lined up better with the shape of the grip. I tried them both a few times, and the 20SF just felt better, more secure.
Then I installed a 6 inch Lone Wolf barrel and heavier Wolff recoil spring. It's a great gun for the hot 10mm loads. Quite accurate and the 15 round capacity is cool! Never know when a herd of feral pigs might attack!
- Thomas