I would say both the positive and negative reviews on Rieder are right. He does disseminate the broad topic of culture in America into smaller topics that are meaningful to analyze, which is good, but he also too frequently rely on high-flown, unreasonably abstract language at lectures. Some of his languages would be hard to understand even in written form. It's not that I'm slow to understand, friends, his language is often something that you would take 10 minutes to dissect when written on paper. It's like he's speaking an esoteric academic article. I don't think this is "well-spoken". We are taught at university to NOT rely on abstract words that save you the trouble of really making a point even in essays, not to mention when speaking. Why then does this professor lecture this way? Pardon my rage but I think it's either narcissism or laziness on his part.
That said, he is really nice in person. He does want you to learn. It's just his speaking habit really sucks.