Professor Manning was a really nice guy and I definitely enjoyed being in his class. He gave clear, concise lectures that went over the material very well. I Perhaps the thing I liked least about his lectures is that sometimes he will ask a very simple question just to check our understanding and no one will say anything because the answer is simply too obvious. Maybe that's our fault and not his but it was kinda funny to see it happen sometimes. Regarding his tests, they were of average difficulty in my opinion. I got reamed by the first midterm and consequently decided I would study much harder for the second one and the final. I did well on both of those. If you prepare for the exams well you should be fine. If you think you know the definition of linearly independent, but you don't know how to prove it, you won't be fine. So yeah if you have the option of taking Manning I certainly think you should (unless its at 8am of course).