I concur with most of the sentiments expressed in the previous reviews. Looking back, organic chemistry (or orgo for short) was the most rewarding class I took freshman year. I do not regret my decision. However, having said that, this class is definitely not for everyone. I'll try my best to help you make an informed decision.
Now, first, a little background about myself. I did take AP Chemistry back in high school. My school offered two years of AP Chemistry, so I had a good background in chemistry. I did get a five on the AP test.
However, coming in, I still felt unprepared. Professor Breslow constantly introduced concepts without proper explanation. A lot of the concepts were also very obscure. For example, he taught us, on the first day of class, about orthogonality. I later emailed my high school chemistry teachers (both PhD.s), and neither of them had ever heard of the concept. His lectures do not overlap significantly with the book, and we were frequently tested on material that were only mentioned in passing. The class was very frustrating.
Now, more about Professor Breslow. He's clearly a very talented and approachable professor. Some of the girls in our class call him "adorable". He also has a good sense of humor, which did make the class a lot more bearable. However, Breslow is not a good lecturer. He never fully introduces concepts, and he rarely ever explains the mechanisms of reactions. He speaks at length on his experiences and projects but gallops over material that is fundamental to our understanding. He is also very hard to hear, and his handwriting can be very difficult to read. Like a Heisenburg particle, you can either listen to him or take notes, but you can't do both. Certain classes are frantic, but other classes are just plain boring. I've fallen asleep in class a few times.
Your best bet is to learn from the textbook, which does a pretty good job of explaining the material. The more studious members of our class take notes directly from the book. Make sure to do all of the suggested problems, as some show up on his exams. I also recommend purchasing some outside help books, like Organic Chemistry as a Second Language. I spent an enormous amount of time reading and taking notes from the book.
On the bright side though, if you are willing to sacrifice a large chunk of your time, the course is doable. I believe that about a half to a third of our class got an A- or above. I managed to land an A, and I feel that I walked away with a good understanding of organic chemistry. However, I sometimes feel that the time could have been better spent on extracurricular activities. but then again, if you can properly balance your schedule, this should not be a major problem.
Breslow's exams can be very annoying, especially for someone coming directly from high school. Unlike your typical high school exam, Breslow's exams only cover about 5% of the material you're taught. If you happen to have studied the concepts covered, you're safe. Otherwise, you'll find yourself in a very bad position. Some of his questions come straight from the exercise problems, but some also come from things that are only mentioned in passing. I feel that his exams are more about luck than about mastering the material.
The course is very time-intensive, but it's doable. One very nice aspect is that you can finish organic chemistry freshman year, which really frees up your schedule. The second semester, with Professor Leighton, is also very chill. However, you'll have to sacrifice a lot of your time as well as many extracurricular activities. Choose wisely.