Funny you should mention DL and 757s-
DL's BizElite 757 used for CA-JFK transcons (and occasionally on SEA-JFK) uses the same F seats that VX uses, and has seatback IFE in all of Y (power in the first 10 rows).
The 757s that aren't so nice are mostly, surprise surprise, ex-NW birds (and I agree, they aren't very nice).