Several times I've experienced significant fade with OE front disc/rear drum setups on moderate power cars. Its no fun to be at speed needing brakes and not having them. Granted I was pushing it in the twisties but that's what a car is for. With drum/drum it would have been much worse.

When I got my drum/drum Challenger I drove it around the block a few times then tore it down. I put 13" disks on the front... along with lots more HP. I haven't overdriven the brakes yet... but haven't had many opportunities to drive it in anger. We'll see.