I would like to note a few observations i have made aswell with the beta.
the helicopters dont have much difference, the strenght of the yaw of the "comanche" vs the "merlin" is pretty much none. even though realisticly, the comanche could rotate at really high airspeeds.
The airspeed of the merlin is pretty absurd aswell. i was able to do stable flight at 390 kph. stable sideways flight at 350kph. and burst speeds in excess of 450 kph.
The more realistic range of collective compared to arma 2 is nice. but all the choppers seems to handle mostly the same. and they are all really easy to fly due to the easy fly handling with the large amount of collective upwards you can apply.