Would Puritans lives be better or worse, if they were like modern Americans?
We think of Puritans as repressed and grim people who had no freedom. But imagine that the Puritans were more like modern Americans.
First, the Puritans were a product of their time. They emerged in opposition to trends, especially religious and social trends, in England that they disapproved of. So if they were like "modern Americans," as defined by the connotations of this question, they wouldn't be seventeenth-century Puritans. Puritans had a notion of "personal fulfillment," it just wasn't a modern notion. In any case, many settlers who didn't share Puritan beliefs flourished in the American colonies, including Jamestown and in New England itself. On the other hand, Puritanism certainly played a major role in shaping the character of the New England colonies in the seventeenth century.