I've read Quiet by Susan Cain and highly recommend it to anyone who is an introvert (or loves one). Most people I work with are very surprised to find out I'm an introvert (INTJ) because I have such a strong and outward personality. They have a misconception of what it means to be introverted.
I have recommended the book to many members of my team at work as well, since as part of a Gamer culture there are often struggles for the introverts to figure out how to operate in what is considered a very Alpha/Loudest Voice in the Room/Extrovert company culture (this is where my strong personality has no issues. I have no problem operating successfully in these environments but do require an enormous amount of quiet, alone time off-hours to recharge my mental batteries).
I've not read Gifts of Imperfection. Based on the description and reviews on Amazon it doesn't sound like something that would appeal to me, though. I've never struggled with the "Lifelong journey from What will people think?' to 'I am enough.'"
I believe in my strengths and I love to learn from failure. I'm all good with that. While I really love to get input/ideas/opinions of others on lots of topics, what they think of me does not shape or define what I think of me. As long as I'm okay with who I am as a person (kind, honest, straightforward) then that's what matters. Dunno. Maybe the description of the book just made it sound a bit too "self-help-ish" to sound appealing and I'm misinterpreting the book's purpose/intent.