The SSM Tier List was made by A15 and was last updated with "Cow" kit.
This tier list woks like any other one and goes from "S" to "F". Unlike some, it has no "SS" tier. This means that no kit is not Ridiculously overpowered.
It is uncertain where the "Guardian" kit lies, as A15 is currently working on other things.
The high damage & knockback "Skeleton" is currently the "best" kit and the low armored & light "Chicken " is the "worst".