Our maintenance guys say they are to be serviced to be in "as new" condition every time they leave the shop. Of course, I believe that's mechanically sound, not cosmetically.
We have 4 Crown Vics with still within the police department. 1 is still in service as a patrol vehicle. The other 3 are used by the police volunteer program. I wouldn't hesitate to use any on a long road trip- meaning I'm confident they wouldn't leave me stranded.
I think part of the equation should be what department the vehicle is coming from, and their maintenance policies.