The discs all the way around was a bit of a drama to the uneducated within the department. I came from another department that bought a pumper back in 1989 that was discs all around and I have hated every rig with drum brakes I have ever driven since that unit. The do have a proven track record on fire apparatus for power, durability and longevity. Remember, fire apparatus (especially a volunteer department in a suburban or rural area) isn't going to see much mileage. Our 2006 pumper (which is what this ladder truck is replacing) has roughly 35,000 miles on it. Our 2013 pumper just broke 10k last week.
I am fortunate that I know a few big wheels in the City of Philadelphia fleet management office and get to pick their brains occasionally. They are responsible for trash trucks, fire trucks, police cars, you name it.....Each agency has some say in what they want but ultimately fleet management has to OK it. Philadelphia has been playing with discs with a lot of success for the last 20+ years. The discs on the tandems came highly recommended by these guys.