3M 680 Prints and installs great and is still just as reflective once printed. You are going to pay dearly for it though......
We do literally many dozens of ambulances, police cars, and fire trucks each year. I just got 3 full rolls of the reflective we use (have a job for 11 ambualnces and 8 police cars right now) in which is about a quarter the cost of the 3M 680. Prints great but none of the others are as easy to install as the 3M. We use Nikkalite M8512 - actually short of 3M 680 it is hands down the best one I have found yet.