There is no single best tool because it depends on what you are writing. ChatGPT is popular for general copy and brainstorming. Jasper is built more for marketing and has templates for ads, emails, and landing pages. Copy.ai is another option that focuses on short-form copy like product descriptions and social media posts. Most of these tools do similar things, so the best one is usually the one that fits your budget and workflow. Have you tried any AI writing tool specifically for marketing, and did it actually improve your copy?