The fact is that there are weak professors everywhere; even at Harvard. It's also true that one student's bad professor is another student's great professor. My College Algebra prof, "Dr. Andre," was a Ukranian math genius with a doctorate from GA Tech. He also had an incredibly thick accent. So many people complained that they couldn't understand him, but I excelled in the class, partially because I'm Russian.
All you can hope is to put off certain classes until you get a better pick of who's teaching, unless it's a time-sensitive scheduling situation.

You're not taking the politics of higher education institutions into account. The best professors to students aren't necessarily the best professors to administration.

At one of the best schools in the country, a professor I knew was told to turn down teaching awards, because if students think you're a great professor, you're not doing enough research. And come tenure time, you don't want that cloud over your head. Seriously.

Also, college is diff't from high school. You aren't required to be there. So professors aren't obligated to do whatever song and dance is necessary to keep your attention so you'll score well enough on standardized tests that they'll keep their jobs. You have to motivate you.

And grad students who teach courses aren't taught how to teach. They get experience by teaching subjects they're hopefully competent in. Students are part of their learning process as they work towards their PhDs.

Even when choosing a school online, it can be hard to really determine what makes that school good or bad. The school that I am attending now is known as one of the most recognized and best schools online. But my reason for attending was because my admissions counselor has extensive knowledge and experience in the field that I am going for and he assured me that my professors for those particular classes possessed the same credentials. Not to mention that my additional choice boasted about being a part of an organization but when I asked how this would help me or how are they affiliated, the answer was "I'll have to call you back." They never did. I can only imagine how helpful those teachers would be.

I went to a school where motivation of the student was the greatest part, most of our profs were researchers, after Freshman year if you were not motivated you were sunk.

That having been said the specific curriculum, the texts used, all vary and do make a difference in how intricate the degree of knowledge you could be expected to get is.

You couldn't go to my university and actually graduate if you didn't go to class, at least in either of the schools of that uni I attended. You could however go to a number of universities in this country and not go to class and pass, I think there-in lies the difference. If you can "not go to class" and pass you are probably not getting you money's worth.

["The key is what Dawn van Emden, Ryan Paugh and others have already said; in the case of bad professors, what are you paying for?"]

You are paying to document your exposure to a particular subject or class. I have always believed that universities should have a way to TEST OUT of every class, but they don't because that would have a drastic effect on attendance. There are many professions that have such involved on the job training that taking a class after the fact is a formality, but many times these people have to just take the class they need to graduate. In this example I blame the universities.

["I could probably teach myself many subjects or learn informally from others very cheaply, but students pay thousands of dollars for this service at the "good schools"."]

The problem today which did not exist in the past comes from employer mentality. 30 years ago a worker could demonstrate proficiency through a portfolio or in an interview, test or discussion. However today, "hearsay" regarding training is not good enough to any employer. Only a class or degree certifies minimum knowledge from an employer’s perspective. In this example I blame employers

["Unfortunately, learning that takes place on your own doesn’t always count toward the coveted degree, which has, more or less, become a prerequisite in today's society."]

That’s why I always say that people should try to document educational or training experience on paper if possible. Also I recommend that if you already know how to do something, go get it documented by taking a class or certification exam, even if you don’t need to study to pass. Universities and employers have forced it on all of us. Studying subjects from books at the library will never be an acceptable form of documented minimum proficiency, ever.