I don't know anything about the other teacher O'Flaherty but I can say that Gulati is a great teacher. Not amazing but definitely worth getting up at 9 am to listen to (for all you considering taking his class in spring of 2007). He speaks loudly and clearly and often makes jokes in class (sometimes at the students' expenses, all in good humor of course). As to accusations of having a large ego in previous reviews and having hard tests...not true. The average for the midterm in fall 2006 was a 72 when he was aiming for a 60 something. I went to dinner with him (there will be signups) and he is a very approachable guy and modest in person.

For some reason the TAs seem to be unfair with problem sets. But do the homework and don't leave studing till the last day and you should be fine: 5 in-class pop quizzes, 5 psets, 1 midterm, 1 final.