Professor Lu is a nice guy. Very accommodating, has a great sense of humor, and has a nice elder "grandpa" vibe that makes him an enjoyable person to be around. You can also easily tell that he is knowledgeable about the field by injecting things he's noticed over the years regarding networking technology innovations.
However, lectures do have some "pizazz" to be desired. They are very bland and he essentially reads off of the slides. I also do not enjoy the fact that attendance is mandatory.
Mr. Ding is clearly knowledgeable. However, he is bland and not very interesting. I did not attend after the first discussion even though it's technically mandatory.