There is a very interesting account of a ba'al teshuva's experience called Journey to Tradition: The Odyssey of a Born-Again Jew by Michael Graubart Levin. From Amazon:
Five years ago [this review written in 1986], when Levin was an Amherst student, he literally stumbled into Ohr Samayach, a yeshiva in Jerusalem that teaches young Jewish men and women the orthodox way of Judaism. He loved orthodoxy's spirited, family-oriented approach and happily shouldered all the customs, rituals, and restrictions. But only for five yearsand then loneliness did him in. Since he no longer belonged to his old crowd, and since, as he claims, "born orthodox" Jews never fully accepted him, he retreated. This well-written, very readable book is important in several respects: it lends credence to those unique yeshivot in Israel that many people hear about but few actually experience; it explains in simple, often funny language what religious Jews do and why; and it reminds the orthodox community to be extra sensitive to the needs of newly religious young men and women. If you read carefully in the review, you'll notice that Levin "retreated" after a few years of being frum, for reasons stated in the book, after some years of keeping shabbos, kashruth, wearing a yarmulke even at work etc. When I read this book a few years ago I didn't realize that and was pleasantly enjoying it and really surprised when he mentioned that he is no longer Orthodox. The book is a very sympathetic account without any hard feelings, it seems. It might be dated by its age. But it's a really interesting read. Suffice it to say, he neither joined nor left Orthodoxy for deeply intellectual or philosophical reasons. I suspect that's widely the case.