It depends on LR.
We flew B757 across the pond ten years ago (MAN - New York) and the flights were absolutely fine. Seat pitch, IFE, food, all as good as a wide-body I had experienced before.
The real issue on these planes is the number of toilets available to economy class passengers. Flying in Europe on a traditional airline with different classes (Lufthansa A321) they reserve the front toilet for Business Class (say 28 people) meaning that two toilets have to serve about 166 passengers. Easy and Ryanair have three toilets for 180 passengers on A320/B737. It makes a difference on a flight if you are hanging around waiting for the toilet and disturbs passengers seated near the toilets..