Have you ever used an English tutor?

Have you ever taken lessons one-on-one with an English tutor?

I've studied Japanese with a tutor, and found it to be a great way to improve my fluency and understanding. We met once a week in a coffee shop for a couple of hours. We discussed various topics, read out loud from Japanese books, and talked about what I should say in different situations that I encountered day to day.

I've also tutored students in English over the years. Sometimes I felt like I was really helping them to improve quickly. But other times it seemed like there wasn't very much improvement. Although I tried hard to be helpful, I worried that the students might have been wasting their money on hiring a private English tutor. Maybe they would have done better in a class, or studying on their own with natural materials like English TV shows, magazines, and novels.

What about you? Have you had a good experience with studying with a tutor for English or another foreign language? Do you have any horror stories to share? Any ideas for how to get the most value out of a tutoring session?