the only thing about fixed pitch is the lag time in altitude response. with a variable pitch you get instantaneous response to both up and down requests from the collective, in fixed pitch you have a lag as the head speeds up or slows down and the wind also plays havoc on fixed pitch. now if you were flying in the house with no wind influence then other then that lag in head speed changes there is minimal difference. cyclic/tail input is the same.

i flew some fixed pitch nitro birds way back in the days and the only differences in overall flight was in hover i had more up/down bobbing and you couldn't Safely stop forward flight and descend to a hover from altitude, you always had to fly down to a hover rather or the lagging head speed would cause you to have a 'not so smooth' decent or you'd have a 'bump in' with the ground as you tried to stop the decent.

kc