I'm an IM resident finishing off an ER rotation at a New York City Community Hospital and I have to say that the ER residents and attendings are a cool group to work with and the work can be difficult in that the pace may be hectic and you have to know how to multi-task. But, its a cinch in the sense that you never have to fully figure out whats going on w/ a patient for yourself as long as you can effectively rule out the top 4 or 5 diagnoses that can kill someone and if you haven't ruled them out or sometimes even if you have, you turf them off to surgery, gyn, or medicine and they figure it out. And 90% of the time its a cinch to rule things out. Too much belly pain and abnormal labs, get a CT Abdomen/Pelvis. Someone altered and/or slurring speech, get a CT Head. I'm not sure that med school even needs to be a prerequisite to do this job; maybe PA school or a 1 year course in emergency medicine. It is interesting to see a patient when they first present and I can definitely understand why people go for this field: good money and not having to have one's own practice w/ all the pains that come with that and shift work.