I don't have any issue with taking notes (provided notes are not expressly forbidden). However, with both MMI and traditional interviews, you want to make sure that you are fully present, listening alertly, and sending the proper non-verbal cues to the interviewer. Don't let the perfect be the enemy of the good: jotting down a few bullet points to ensure that you hit all your points may be a good idea, but relying too much on notes could be detrimental.