The overwhelming consensus from email marketers, documentation, and experts is that the new Gmail Postmaster Tools dashboard should be trusted more than the old one for spam rate data. The new dashboard provides more granular insights, detailed overviews of email performance, enhanced features, and reflects the current state of email deliverability and spam rates. Google is deprecating the old dashboard, making the new one the only viable option. Although some marketers found the old dashboard updated faster, the new dashboard's accuracy, improved data processing, alignment with current spam policies, and better insights into email deliverability make it the preferred choice.