TSR/WotC's #AlternityRPG is a masterclass.
The MOGA system seamlessly incorporates "critical success" into its core task resolution mechanic. You instantly know what your odds of success are, and your odds of 'critical' success, and they are based naturally and organically on your characters's abilities.
The fiddly hit point system and armor-as-DR mechanics take getting used to-- but they're a model for how armor can be most useful when the person wearing it needs it the most.