I don't know what the deal is with the pneumatic system on our jets, but it must have something to do with the cargo configuration. Anyhow, on the 757, you gotta turn a pack off in flight otherwise the noise level is terrible. Thing is, you turn one off and, what does the other do, go to "high flow". That's almost as bad. 75's are crazy noisy.
Anyhow, I was gonna say the 767 is quieter. The wider cockpit is nice. As far as how they fly, they both fly really nice, compared to the 727. That 727 was just dang hard to get a good lander out of.
We'll assume automation off, as that's apples to apples, but I don't see that big a difference between the 75 and the 76. The 76 has the outboard ailerons with the flaps down, which, I think, makes it more responsive than the 75. You'll always be faster in the 76, which makes things happen faster and calls for more runway. They both land pretty nice. The 75 will drop the nose bad on roundout, so be careful. The 76 does the opposite, the nose will raise with ground spoiler deployment, so you have to temper that. If you were in a 76, and were thinking 75, and added back pressure in the roundout to keep the nose from slamming down, you would aggrivate the 76's nose up tendency and maybe get a tailstrike. That's bad.
Anyhow, I find both pretty easy to get a good landing out of, especially the 76.
They both autoland far better than I could do on a consistant basis. It's an amazing thing to watch. It's just like in the sim.