Very subjective...
If you love the KS, probably nothing.
It has a super long, sleek and flat profile. The steel takes a great edge, but isn't known for retention.
So if you hate sharpening, it's probably not for you, and maybe a R2 Saji is a better choice.
If you dig knuckle clearance, it's probably not for you, and maybe a Takeda is a better choice.
If you don't like to be bothered with the maintenance, maybe a Suisin IH is a better choice.
If you dig one off customs, maybe a Rader is a better choice.
If you like western style handles over wa, maybe a Hiromoto is a better choice.
Etc..etc...etc....