I do have experience attending a few design reviews and also leading one. From my experiences design reviews are exactly as everyone has been describing. They are important milestones within the medical device development cycle, and are a part of the required design control process. Design Reviews do require a lot of preparation, and the way in which you present the information in the design reviews is also very important considering some of the audience is most likely unfamiliar with your project (i.e. independent reviewers). I do not think anyone has mentioned the concept of an independent reviewer in this thread yet, and I am not sure if they are required by the design control procedure. At my company multiple independent reviewers are required to attend the design review. These independent reviewers are not a part of the project that is being reviewed, and each have different areas that they specialize in (technical, quality, etc.). All of the independent reviewers must agree on all of the design review content being presented and sign an approval form. If any of the independent reviewers have questions or concerns that cannot be answered or addressed during the design review they become open action items that must be completed before the next design review.