Helzner is a very knowledgeable, smart professor. He enjoys the socratic style of teaching - sitting in a chair posing questions and poking holes in answers. That's a great technique but he doesn't often go beyond it and present lecture material to supplement the questioning. That means you won't often have a comprehensive treatment of a concept or material in class, which you may or may not prefer.
He is a brilliant professor who respects answers and students. His give and take in class is always generous and enjoyable. His math background makes him vulnerable to describing everything in math terms and symbols.
Excellent professor if you like his approach. Clearly brilliant.
Regular readings, midterm and final paper. Not too heavy but challenging material and enjoyable to think through.