Reviews of professor Hakan Gogtas

Rating: 5.0/5, difficulty: 3.0/5
Dr. Gogtas' course was perfectly balanced between challenging and engaging. He gives you all the tools you need to do well, and builds a solid foundation of the material you'll be using in the program. His TAs are really helpful, and he provides a practice midterm and final. It's really easy to do well in the class. Phenomenal professor and course.

Rating: 1.0/5, difficulty: 3.0/5
While well-meaning, I don't think Gogtas has the know-how or understanding of the material to be an effective professor. He will NOT give you comments on your final if you ask for them and WON'T release your final exam grade either. This class may make you feel incompetent but don't be surprised if this class is your worst grade for the degree.

Rating: 1.0/5, difficulty: 3.0/5
Worthless. He's just retelling the textbook. I don't think he even understands most of the content. Shame on you, Harvard, to pick him to teach an admission class. He will easily make all your efforts in vain. He has no interest in your feedback whatsoever. I am so surprised he's still there.

Rating: 5.0/5, difficulty: 2.0/5
Contrarily to things I could read (which worried me before taking the class), Hakan is very knowledgeable and a very good teacher. His insights are actually very professional. 
The class would benefit from more structure to become excellent. But again many materials are prepared by Hakan so you should be able to pass easily if you put the effort.