Even I get caught up in stories of defections.
Over on a Lutheran discussion board, a guy announced he was "defecting back to Calvinism". You can read it here:
These are always interesting to read. I could probably post a Lutheran response:
"You mean, you're going to embrace a false view of the Eucharist?" "You're going to embrace the heresy of limited atonement?"
These seem to be the issues that Lutherans dwell on. In the first, Calvinists and Lutherans should at least agree to disagree. In the second, Lutherans should at least read up on the Reformed perspective on limited atonment before speaking about it negatively. In other words, go out and get a few books from actual Reformed authors. Read their points and be prepared to know what you're talking about.