Definitive answer time:
If you're considering the response of the aircraft to vertical gusts then the front is the best. When the aircraft hits an upgust it heaves upwards but also pitches nose down, hence towards the front of the aircraft these motions to some extent cancel each other out, while down the back they magnify to make things unpleasant. (This is why most accidents involving broken bones occur in the final few rows).
If you're considering the response of the aircraft to lateral gusts then the middle is the best as it will minimise the acceleration due to any yaw motion.
Which is best? Well thanks to those massive wing things being designed to generate lift upwards, the aircraft has a far stronger response to vertical gusts than lateral ones.
Hence, finally,
the front is the best.... But you're more likely to get killed there in a crash
.