This is my favorite of all of Austen's books. Not the wittiest or with the most appealing heroine--that would be Pride and Prejudice. Nor the funniest. That imo would be Emma. I do find Wentworth the most appealing of the Austen heroes though. He's a self-made man and the theme of merit versus aristocratic privilege and pride runs through the book.
Which is not to say I don't feel for Anne. She's a quieter heroine than you usually see in Austen. Someone that seemingly was too easily persuaded years ago and seems destined to end her life alone.
I think if for nothing else, this book would have earned a place among my favorites because of one scene. My inner feminist cheered at Anne's defense of women, and their faithfulness in love. And truly, if you aren't melted by the letter Wentworth writes to Anne, you have no beating heart.
As always with Austen, there are winning touches of humor throughout that leaven the drama. Persuasion isn't as comedic as Emma or Pride and Prejudice but it's still a welcome element.
Austen has had an upsurge of popularity because of several adaptations in the 90s. I do love the Pride and Prejudice miniseries and the films of Emma and Sense and Sensibility but I don't feel there's any film adaptation of Persuasion that does it justice. So if your impression of it comes from those films, all I can say is the book is much, much better!