I've had Mark as my TA for two semesters now, and I really hope that I have him again for a philosophy class next semester! He's honestly a really devoted, awesome TA - and this is only his second semester as one! I can say for both classes that he was really accessible and approachable, and, like the previous reviewer said, almost always added more office hours - especially around the midterm or exams. And if you couldn't make his hours for certain weeks he was more than happy to make an appointment with you. His feedback on papers have always been really helpful, and he never seemed to mind answering even the silliest of questions, and seemed to genuinely care about the students understanding the material!