I know people who were dissatisfied with charting, but this was because they did not want to have the discipline required. My friend got pregnant on it, but she had one very ambiguous temp rise (like 0.2 degrees) in the morning and they had unprotected sex immediately that morning. The next day, her temp was down again and it didn't have a big rise until the day after that. She blamed charting, but it was really user error.
Get used to me. Black, confident, cocky; my name, not yours; my religion, not yours; my goals, my own; get used to me. -Muhammad Ali