ChatGPT Pro has replaced Gemini Notebook as the author's favorite research app, a shift they did not anticipate. The author had used Gemini Notebook since its launch for research, organizing work, and studying, but gradually switched to ChatGPT Pro's Work mode over weeks. Work mode builds a workspace around an initial idea, with two panels on the right: Outputs and Sources. The Sources panel holds references, which the author prefers to add manually, verifying any automatically pulled references. The Outputs panel can turn research into tangible items like documents, spreadsheets, or websites, and the author has built several sites using it. Work mode also allows follow-up questions, refining research, and managing sources, similar to Gemini Notebook. The key reason for the switch is that Work mode is only one part of the paid ChatGPT Pro service, eliminating the need to jump to another app after research, as it can also schedule reminders and send messages.