Eh. Manning is... fine. I didn't get anything out of lectures. Tests were pretty straightforward though. If you have another option I would probably take my chances if I were you, but also he doesn't flat out suck. He's just not good either.

Manning is great! His lectures are at times a bit hard to follow because he relies too much on words like "this" and "that" instead of specifically stating which theorem/lemma/whatever he's referring to, and occasionally skips a few steps when going through proofs, but he's always happy to clarify if you have questions!
Very approachable outside of class and during OH as well!
His homework can be a bit long, but he provides useful hints on many problems (and often the problems in earlier homeworks show up in later homeworks, too, which is nice because then you have something to refer to).
Only 1 midterm, per department policy it was 24 hrs long -- honestly it was pretty easy? I spent like 2.5 hours on it, not because the questions were particularly hard but because I worked really slowly. The median score was a 98.
The final was a lot harder, per department policy it was 24 hrs long, and I spent like 9 hours on it. The final was about 30% of our grade, though, so it isn't as make or break as finals usually are.
Overall I enjoyed this class and am taking 110B with him in the spring! Word of advice: the textbook is easy to read and explains things pretty thoroughly, highly recommend reading it!

Professor Manning is the best. He follows the textbook and doesn't go outside of the box. He's lectures are great as he goes over the book line by line so you don't need to take notes as you can find everything on textbook. HWs for this class is 40% of your grade which is insane and the exams are really similar to HWs. Overall I recommend him for this class and every other class that he teaches and trust me IS NOT HARD TO GET A IN HIS CLASS.

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).