Fantastic and engaging lecturer. Rarely felt completely lost during his lectures. Homeworks are generally easy, but exams are quite difficult (especially given the time constraint).

If you have to take linear, take it with Obus! His lectures are really well organized, and he's good at explaining concepts and answering questions, a rarity in the math department. He writes everything down on the board, which was annoying at first, but helps a lot when looking over notes later. The two midterms weren't bad, but the final was unexpectedly hard.

A great professor and a great person! His tests were kinda really hard, but he is generous with partial credit. Like really generous. He's a dork in the best sense of the word.

Just go to his website and take a look at his CV. Knowing a lot of stuff and teaching them well are two different things, but he lacks neither. With that said, this is probably not an easy A, but if you are going to take it at some point, don't take it with someone else. He'll teach this course in Spring 2014!