I was on a 767 from LHR to IAD a week ago with an upgrade to C. It was comfortable enough, but to my mind not as much C space as on a 777, and, of course, certainly not as much as on a 747-400. Also, 767 storage is very minimal in the overhead, no depth compared to 777 or 747.

Last month we were on a 767 SFO-OGG (Maui) in F, and it was about as comfortable (!) as F in 737. Don't know if E+ was available.

Flyer420 in Seattle