From what I understand, SSO works completely well for new customers. You can set up and access all accounts with one login. The problem I, and others, have is because we are legacy users of 2 or more products prior to their acquisition by Intuit. For example, I have done my taxes in TurboTax for the past decade. I have a Mint account dating to before Intuit bought them. Last tax season, Intuit sent me a marketing message to my Mint login asking me to login and do my taxes with TurboTax. I actually thought nothing about it and followed their suggestion, did my taxes, and realized near the end of the process that I had made a mistake by following their direction. I saw this because my historical returns were not available to compare. But, based on their messaging indicating one account & one login, I naively assumed they were being honest and I could move forward and simply link the accounts. That proved to be wrong.
