Evaluate your professional judgment under time pressure. Measure your ability to prioritize the quality and veracity of your message without compromising the timeliness of your response.
I believe both are important, but if I had to prioritize, I'd choose accuracy. Fast communication loses its value if the information is incorrect or leads to misunderstandings. However, accuracy shouldn't be an excuse to unnecessarily delay responses. The key is to communicate what is known for certain in a timely manner, clarify outstanding points, and update information as more data becomes available.