I don’t think you could go badly in any situation. I always dressed formally for my interviews because it felt more suitable to me. I want them to understand how important the interview is to me and how well I prepared.

However, I believe that if the interviewer takes a more free position during the interview, you should respond by communicating more casually. If they talk professionally, I will match them.

I dressed business formal for my Accenture interview, but the HR wore jeans and a blazer. He was also more informal and approachable to talk with. It was fantastic. We had a discussion rather than a Q&A.