I just noticed this when flying yesterday and was wondering if I'm the only one that has experienced it.

When I started playing Arma 3 and flew around in a helicopter I could not really do my low flight like I do in Arma 2, like 27-32m above ground which I use often for hiding from tanks and AA. Problem was that the heli felt so heavy, and I hadn't enough lift to really follow the terrain like I originally do. I tried with the keyboard and noticed instantly that when pressing Q I'm gaining altitude faster!
This is a problem I noticed with ground vehicles too. Cars accelerate slower when using the LT/BT keys on the 360 controller.

TL;DR: 360 controller inputs gives slower lift/acceleration than keyboard inputs!