Please suggest a Santoku for around $100
just need your suggestions on this knife, i will be using this knife for medium to light work in the kitchen.
Of the 4, I say Hiromoto Aogami is probably the best one -- assuming you don't work in a professional kitchen. Have you used an aogami (blue paper) steel before? If you have not, I think you will like it. You can sharpening the edge very low, much lower than CarboNext, and it holds the edge.
CarboNext is probably best compromise for a busy kitchen where the knife will see a lot of water and acids. It is, however, boring for you because you have several CarboNext knives already.
I think Kagayaki is good, but I feel you are beyond and above the entry level knives.
I feel the same for the Misono. It is an entry level knife.
You already have a few CarboNext knives, right? Do you want another CarboNext Santoku? I actually have one, and I think it is fine. Take a good edge and easy to sharpen.
On the other hand, I think a Tojiro DP Santoku is pretty good too. I don't have a Tojiro DP Santoku, but I have its gyuto. I feel the Tojiro DP knives are blade thin which s good for medium to light work in the kitchen.
That being said, Tojiro can be a bit "boring".
If you don't mind a carbon steel edge (aogami super), then the Hiromoto AS Santoku should be a good choice. Keep really good edge and excellent edge retention.