The blog post by Paul Scanlon details his experience upgrading his website to Gatsby 5, emphasizing the importance of a structured approach over a "YOLO" method when dealing with major version upgrades. He highlights the changes in Gatsby 5, such as the necessity to update to React 18 and Node 18, and discusses challenges like GraphQL schema adjustments and React hydration errors. The post also mentions the use of Node Version Manager (nvm) for managing Node versions across projects to ensure consistency. A notable improvement with the upgrade is the significant reduction in build times, with Gatsby 5 offering around a 47% faster build speed compared to its predecessor, partly due to features like the Slice API that optimize build efficiency. Paul concludes by advocating for a careful upgrade process to avoid potential pitfalls and maximize the benefits of new features in Gatsby 5.