I will have to state that MedEvac/Air Ambulance is one of the most rewarding job I've ever had! (Army side too!!)
Base living and the schedule make it great; 12 hour shifts, 7/7, and home every day. When I was covering the fixed-wing side, I could respond from home and still easily make my dispatch time so that was a bonus.
As posted above, there are a LOT of transports that really could be done much cheaper AND with much less risk for the patient. However, when you land on a highway, take a patient that has just been cut out of a car, get them to the hospital safely and quickly, and see them later recovered, the job isn't "just a job". For me, even if I went home at the end of a shift having not flown, I still felt that I was serving,
On the fixed-wing side, it was much less exciting but was still pretty fun because there were different airports/approaches and something new almost every day.