Pros
Good learning experience especially if you are a student. You get exposure to all types of emergencies and learn more about the treatments and diagnoses associated with various signs/symptoms. You get great experience using medical terminology correctly and you'll be awesome at charting and being thorough if you decide to pursue other medical careers. Also, you get to watch procedures, examinations, and other interesting things.
Cons
It can be stressful at times, and there are definitely shifts where I only have time to take a 5-10 minute break for the entire 12 hours. You can't plan on getting off on time, either. It can also be difficult sometimes switching between and memorizing the way each specific doctor likes their charting to be done. Lastly, you'll learn that there are a few doctors out of the many you will be charting for that can be difficult to work with - some of them can be rude to the staff at times and create chaos when things get busy.