personal comparison forward MCE vs. exit row
763 JFK-BCN
Mrs. G and I have traveled together in row 11A/B on the 763, and found it quite roomy and comfortable (didn't get upgraded, sigh!).
77W LAX-LHR
Again, not upgraded (only the 2nd time since 2010), and I had chosen 31L rather than row16, because only middle seats were available in foward MCE cabin. My impressions: 77W row31 seats are not as good as 772 row31 seats, as the seat is quite narrow and there's a galley quite close. Even though it's the secondary galley, FAs do tend to chat in there while pax are trying to sleep, and that's distracting .... plus there is bright light that spills out whenever the curtain to the galley is opened.
While taking a short hike around economy (not that short, the 77W is LONG!) I took a good look at 16A and 16L MCE seats, which don't have a nearby galley and which seem to be a bit wider than row 31.
The bottom line, in future, I will avoid row 31 and favor any non-middle seat in MCE, with row 16 preferred.
p.s. the 77W's IFE is really great, even in econ, and as y'all know, the 772 IFE stinks.
p.p.s. I did get upgraded returning LHR-LAX, and after lunch slept soundly for 4+ hours. Those 77W J seats are really comfy!!