Reading Puritan Portraits was a win-win for me, because I wasn't that familiar with Packer, either (though several of his books have been lingering in my "To Read" stack). I found the book to be a wonderful introduction to both Packer and the Puritans he admires.
Puritan Portraits is a series of introductions Packer wrote for books by various Puritan authors. These are no ordinary introductions; Packer not only encourages the reader to meditate upon the material, he exhorts them to put what they read into practice. From the introduction to Stephen Charnock:
Trusting, loving and following Jesus necessitates keeping the cross in view at all times. Our living Lord calls for what we may call cruciform discipleship, clear-headed, open-eyed, and whole-hearted. 'May I never boast except in the cross of our Lord Jesus Christ, through which the world has been crucified to me, and I to the world' (Gal. 6:14). The cross must shape our faith and thereby reshape our entire lives. (661)
The Puritans felt that reading should encourage our spiritual growth. I believe Packer's work in this book does just that. After reading Puritan Portraits, I have resolved to read more from the Puritans and more from Packer as well.
You can read the other reviews at the Puritan Portraits Blog Tour.