Weiss is definitely the best professor I've had at UCLA. Brilliant guy and very helpful. The only office hours I've ever attended were his and it was more for discussion and stories than help in the class. He is very well connected and willing to help you with anything inside or outside of his class. He hooks everyone up with lab positions and will talk to other professors about you to get you a position. I still see him around and say hello and talk a bit. What a guy.

Warning: this class is A LOT of work. Weekly homework, literature assignments, and readings. Add that onto a final project, poster, and essay. Oh and midterms and finals, of course.
However, the class itself isn't that bad, and I don't regret taking it. Paul really does want all of his students to do well, and he'll help you get into a research group if you're set on one already. The TA's are also pretty cool, although their discussion worksheets do not help at all with the midterms and finals. If you enjoy learning chemistry for the sake of chemistry (like me), you'll like the class.
The bottom line is, if you're willing to put in the work and effort, you'll do fine in the class. It's whether or not you're willing to do all that work (as in, I took 4 classes that quarter and 20BH was half of my homework/studying time)

Professor Weiss is the smartest man I've ever met! He made this class very interesting and helpful for future purposes.
IMPORTANT NOTICE: This class is extremely challenging. If you do not have the time to fully invest daily hours of work for this class, do not take it. This class' workload is 3 times more than the regular Chem 20B class. There are creative problems to do each week, literature assignments, and also homework from the book. On top of that, there is a final project (poster + paper) that must be completed and is worth 15% of your grade. The only way to achieve your best is to try very hard on the homework (worth 30% of the grade), and to try and score above average on the tests.
Also, stay in contact with the TA's because at times their information is very confusing and the guidelines are difficult to understand. My experience with the TA's was rather disappointing because of their harsh grading and lack of communication, so please make sure that you precisely understand want they want. You can always ask Paul for help if you feel lost.

Paul was a wonderful and approachable professor. The class itself was tedious (so much homework! There's weekly homework problems, a poster presentation and paper, creative questions, and literature assignments), but the exams were reasonable as long as you study. Much of the class (besides a few concepts) was a review of AP Chemistry, so the concepts weren't too difficult, but Paul definitely makes interesting test questions that requires you to apply these concepts to new scenarios.