Joelle's class is pretty good. She's a very nice person and is obviously very good at math. I've found at Columbia that sometimes the smarter the instructor, the more difficult it is for them to explain things to you in layman's terms. Let's just say she's very smart and sometimes doesn't remember that some people in the class haven't taken math in years.
She definitely adds points for class participation and there was some extra credit at the end of the semester. Joelle really wanted us to succeed and valued improvement throughout the semester, which was cool. She even came in to review with us on a Sunday before an exam because class was cancelled one day. Although it sucked to go on Sunday, the fact that she was willing to do it, was extremely appreciated by the class, especially since many of us worked full time and didn't have very flexible schedules.
Bottom line? If you take this class, show up, pay attention, do the optional homework assignments and be sure to drop by the help center or get a tutor before the exams: it will pay off in dividends.