Do not, I repeat, DO NOT take Calc III with this teacher. Do whatever you can to switch into a different section. If you can't and you're stuck, well... best of luck.
I thought in the beginning of the semester that I'd cut Groman some slack because he's a recent grad student that was teaching the course for the first time... yeah well guess how long that lasted. He is hands down the worst mathematics teacher I've had here at Columbia. He cannot teach, he just can't. He stutters over his lackluster explanations, his handwriting is constantly confusing, and the little writing that could be understood in the chalk board isn't even visible because the man has a habit of standing in front of everything he actively writes. It didn't take long before I resorted to reading the textbook to learn the material because he just couldn't teach -- it remained like this throughout the entire semester.
But as if his teaching wasn't horrible enough already, his exams were all substantially more difficult than any other section I knew about (Dobrovolska, De Silva, etc.). The average for the first and second midterm was a 55 and a 61, respectively. The final wasn't any easier either. And oh yeah, I almost forgot! His weekly hw assignments were also tediously long and more difficult. He made a habit of assigning 20+ problems every week, and a single problem could take over an entire page to complete. Great algebra practice right?! Well that's not why I decided to take this course.
If any of this doesn't trouble you, then by all means take Groman's class. But I warned you.