I have always liked Rachel Nichols. She has the looks, but it's far more than that. In her debut on CM she knocks it out of the park. Seaver has natural instincts and I thought Hotch was a little tough on her.
As for the story, there were some excellent red herrings, but I saw something revealing just before any of the agents figured it out.
I agree though with a problem posed by another reviewer. Gun or no, the agent who was impressing the heck out of everyone at the Academy, including physical skills, acted more useless than Spencer when her skills were needed. (Actually, the supposedly clumsy Spencer has handled himself fairly well most times physical skills were needed.)