“Do you use a plumber who is an upstanding wonderful person but a lousy plumber, or a guy who is of lousy character, but knows how to fix the plumbing very well?”
I actually had to fire a plumber who was a great plumber but a sleazebag in his personal life and decided he only wanted to be paid in cash. My Rav had quoted Rav Soloveitchik z’tz’l as saying that it is asur to do business with unethical people.