Wendy's is the best, because they have the most juicy chicken and best breading. It is the spiciest, and sometimes you get to the edge of the sandwich and there's extra breading. It's crunchy, peppery and delicious. It is also the biggest piece of meat.
Jack in the Box is second. It's not as spicy and the chicken is not quite as nice a texture. It's not as big, but it will do.
Chick-fil-a is third. Quite spicy, but a little dry. Also, who puts pickles on a chicken sandwich.
Burger King will always come in last. Why? Because the chicken isn't spicy. The only thing that makes it a spicy chicken sandwich is the sauce. And I DON'T like sauce. So, they lose.
McDonald's has a new spicy chicken sandwich, which I have not tried. It will soon be seen where it falls on the continuum of superiority for spicy chicken sandwiches.