I'm on my 9th class, one more to go. I found that Machine Learning had decent involvement from Isbell (he'd chat with us on Slack) and that Operating Systems and HPC and excellent professor participation -- they would hold weekly office hours (video conferenced) and were active on the forums.
There were 1 or 2 of my earlier classes that did feel phoned in, though (but did have strong TA involvement at least).
"Art for Art’s sake is an empty phrase. Art for the sake of code, art for the sake of the terminal and the OS, that is the faith I am searching for." - Salvador Dali