EM - deal with patients who are dying or who want to kill you. Make a decision now or someone will die. Work for a hospital that will screw you every chance it gets in an understaffed, overworked, underfunded ER. Half of your patients have little to no insurance, so you have to make a living off the other half. And they are mostly in pain and/or extremely anxious as are the various family members, friends, acquaintances, interested bystanders who are packing in the room wanting you to do something NOW, "or we are going to sue you!!!!!" You could work 6 am - 6 pm one week, 6 pm to 6 am the next. And the nurses all hate you too.
PM&R - comfy clinics and rehab floors where you can sit down and think about problems for a while - very rare that anyone is going to die soon. 8 am - 5 pm M-F. Nice nurses. A few crazy patients, but mostly ones grateful for your help.