Bretton Barbarians: Savaged Kingmaker
I dislike the fact that bennies can be used to re-roll a critical failure as these moments create some of the most memorable moments in a campaign, especially the PCs/NPCs overcoming them.
I think that at any point that ‘snakes-eyes’ are rolled (including re-rolls) it constitutes a critical failure/mishap.
The person (starting with the player that just rolled the failure, and continuing in reverse initiative order until the GM selects one) that can come up with the most interesting result will be awarded a bennie (this is a reward for adding to the campaign story).
If all of the descriptions are deemed too mild, the GM is left to come up with a description and he receives a GM bennie for each Wildcard NPC and group of Mooks.