I would almost prefer a narrow-body. You're guaranteed you won't wind up in the dreaded middle set of seats, and your odds are much better that you'd be able to to get a window seat. To me, really, it all comes down to seat pitch. If I had the option to do a long-haul on a narrow-body with 34 inches of pitch or a wide-body with 31 inches, the narrown body would win hands-down.