I've been on 747's for every trip there and back. Fully loaded and about max fueled (KJFK to RJAA).
What has always been evident is the level of acceleration when the captain hits the throttles. Pounds you back into the seat pretty nicely! What a pile of THRUST. :o
But I have never felt any "jerking" or major changes in acceleration. Smooth decrease in percieved forces as the plane accelerates to speed.
And it STILL amazes me every time the wheels leave the runway and we are climbing out that all that weight can actually FLY!

best,
.......................john