I find the issue with seat width is more about how close you are to your neighbor. What I dislike about the 767 is that you're squeezed in there and have a lot less elbow room and "neutral" space than on the 330 (and most other J configs). You also get the I've-got-a-stranger's-feet-near-my-head thing going on when reclined on the 767, which creeps me out. (plastic shell on the 330 appreciated in this regard, feeling of privacy much much better on that plane)

If I objectively rate seat comfort alone then I agree with pbarnette there's not much difference at all. But, in comparison, the overall experience on the 767 feels dated and more cramped - not helped by the miniature IFE screen.