I would submit that alot depends on climate, maintenance and adjustment (if necessary). I've been doing repairs on everything from cars to buses for over 45 years now. Here in southern Ontario, because of the climate, and the use of road salt in the wintertime, disc brakes, especially rear disc brakes tend to be subject to issues due to corrosion, which make them less effective than they could be, which usually means they need more maintenance than drum brakes. Vehicles with 4 wheel disc brakes (when properly maintained and adjusted) tend to stop more effectively than vehicles with a front disc/rear drum setup (once again, when properly maintained and adjusted). In my current job, I do repairs on transit buses. The buses at the shop where I work were recently replaced. The old buses had 4 wheel drum brakes, and the new buses have 4 wheel disc brakes. I've driven them both, and to me, there's no significant difference in braking capability in brake efficiency or stopping distance between the 2 vehicles. In a normal everyday street driven vehicle, in this part of the world, all things being equal, while the 4 wheel disc vehicle may stop a little better, over the long term, it will probably require more maintenance and repair than a disc drum vehicle, and overall, the difference in brake efficiency is not a whole lot. For my money, I'd rather have the disc/drum vehicle. Having said that, in a more southerly climate, where rust and corrosion isn't as much of a factor, then the 4 wheel disc setup would probably be a better choice. Just my $0.02 anyway.
