Honestly, if you have Prof X there is no real point in watching the lectures. You will succeed more easily through reading and understanding the textbook and completing mastering genetics.

He was fine.

Read the textbook and actually try to do the mastering genetics.

This course was rough. The evaluations were always strictly timed (50 minutes for 20+ multiple choice and 2-3 short answer questions). Though the tests were non-cumulative which made them slightly more manageable. Mastering Genetics is a must, and many test questions are lifted directly from it, or numbers are altered. Textbook is necessary solely for Mastering.

Dr. Xu's lectures were fine, though sometimes because of his accent concepts were difficult to understand. However, he did not seem to want his students to succeed and at points, it seemed, made the course more difficult in order to reduce student success.

Practice. Practice. Practice. Keep on top of Mastering and review mastering exercises when studying for your tests. Also, make sure you understand all the concepts and keep on top of them. You'd be in for a rough time if you fell behind since this course is incredibly dense in content.