've been flying long haul since the late 60s and a large proportion of those flights have been on a 747 and about my only complaint was that the further back you were seated the more movement there was even in still air.
Over the years I had the 'pleasure' of travelling on the middle last rows of various 747's as I found that this was where on not full flights where you might well find enough empty seats to be able to lie down and sleep. Disadvantages were smoke, if there were many smokers on board you were passive smoker of the year as all the smoke seemed to head to the back despite filtration and the dreaded chop as the massive tail bucked and weaved to countermand the front of the aircraft. I got used to this and learned to love the movements whilst prone in slumber. I never had the pleasure of the sweet spot in (row 2 ?) but did travel in the hump the odd time which was nice.