Mistman is a powerful navi that has taken out many opponents in his day. They just didn’t have a chance against his awesome power. Mistman will always win in the end. Mrs Mari doesn’t have enough skills to win. Mistman wins.
Mrs Mari can’t really fight. She’s one of the background characters, who is just there to be there. She’s never had too much of an impact on the story. Vegeta could take her out with his aura alone. Vegeta wins.