I'm rotating there right now (this is my last week - time flies!) And I absolutely love it. I mean, it rocks - you see everything: tons of trauma, crazy pathology you've only read about... if you like county, you'll love this place.
There's an hour lecture every weekday by an attending, and these are generally very good; there's also Thursday (9am-1pm) grand rounds which is fantastic. Some of the attendings here are legends and working with them has really been like icing on the cake for this rotation. USC isn't for everyone, and you do work very hard, but I think you get a lot for your efforts.
Let me know if you have any specific questions and i'll post my answers.