I like both and don't prefer one over the other. Not a lot of differences to me, except three features on the 773 I positively like :

1. The expanded galley area on the 773 between the first and second Polaris cabin provides room for me to stretch and stand during the long haul flight.
2. There is a gap between the wall and seat in the odd window seat. I have found that gap is a great place to place my phone (so it does fall under the seat), iPad, note pads, reading materials, eyeglasses. Due to the narrower fuselage, there is no such "gap" on the 787-8/9/10.
3. Large lavatory near door 2L for changing in and out of pajamas.