I think they're free, the online ones are and I quite enjoy them even if I know some of the information they're handing me. Knowledge is power my friend.
I think for someone who needs computer help in general, not just switching from Windows to Mac, they could be really helpful. Looking at online support, not just when you have a specific issue, is helpful as well.
A friend went to one of the Final Cut workshops and said it was really worthwhile. If you're using the Pro Applications then I'd say it definitely is worth your time.
Assuming getting to an Apple store is not a major inconvenience, I would say that the training for any area where you are uncomfortable or unknowledgeable is worthwhile.