Sat in the rear a couple times across the Pacific in the 777. Seems to be a nice, rubber like bouncing motion in turbulence. Found it relaxing and put me to sleep. Personally they should 'make it bounce' like that when it's smooth.
More concerned with flying so long over water with 'only' 2 engines. Bring back the 747 I say. Who cares if it costs a little more to fill up at the service station?