This 757 vs "whatever" is only an issue if you are travelling with a partner in "Y".
Thus unless you are trying to compare vs a 767 / A330 which have 2-3-2 , 2-4-2 then "3-x-3" / "3-3" is the standard product in "Y" with possibly a few variations at the rear due to cabin size.
The issue is much more down to airline, & thus Food, Seat Pitch & IFE subject to ones priorities.
fa2fi
Most of the transatlantics are much of a muchness no matter what is painted on the tail or what kind of plane it
Absolutely agree, simply because there is very little variation in these 3 criteria on current scheduled offerings in "Y"
There was however very little in common with the IT's 757 services out of NCL & that of the scheduled transatlantic product, i.e. Seat pitch terrible, no screen back TV & definitely no AVOD, & IF there was food then zero choice. These comments are bourne out of personal experience in the 90's on half a dozen or so family IT's to FLA.
So why did I put up with it? quite simple CONVENIENCE, the flights went where I wanted to go when I wanted to go & as I always used as argument to myself, then in my experiences, they always fulfilled their prime objective i.e to get me & may family where I wanted to go SAFELY & ON TIME ! & everything else was a bonus.
In retrospect I did not actually see these flights as "cattle wagons" something that I later took the view of when often doing the TFS run. As an aside I recall one trip to TFS in the early 90's on an MD80 I think it may have been OASIS, I only remember this as it had a 2-3 seating config. i.e. there was a 2 seat offering & from recollection the trip was awful, adding further weight the suggestion that at the end of the day it's the airline that counts.
So come on UA
show the North East what you can deliver, as for myself then my wife I will probably give them a try, though these days fortunately it's up front for us, so it really does come back to my original criteria CONVENIENCE, SAFETY & ON TIME.