I teach a class called using your DSLR....and I think it's a great course.
We cover many of the main features/controls of the camera, like Auto Focus modes, Metering modes etc. Of course we cover the basics of exposure; shutter speed, aperture and ISO, but we also go into great depth with metering. How to go from a working exposure to proper exposure. Right from the start, the course is geared to teaching people how to shoot in manual mode. It also has a ton of in-class exercises, so it's very hands-on.
I think it comes down to how you learn best. Some people can pick up a book and learn all that they need to know, while other people could read the book 10 times and still not have it sink in. Others can learn by interacting with people on forums like this, or just reading many websites....and there really isn't anything that you'll learn in class, that you can't get from somewhere else. But most people also learn best when they are in a face to face setting, and then they are forced/encouraged to go through the exercises themselves.
Some of the more advanced students, who come into class knowing most of the material, tell me that it took them months or longer to learn all the stuff we cover in 12 hours of class time.