Every school has a "nasty" ochem professor. Take the hard professor and work your butt off. It'll pay off. Ochem is difficult for premeds because they are stupid about studying it. Once you realize it's not rote memorization it'll pave roads for you. The amount my problem solving and intelligence improved due to an extremely difficult ochem series is insane.
You also have to make sure it's transferable. Ochem isn't like gen chem there isn't general topics that are planned out for every class. Academia has not really assigned an order so many things are jumbled up.