The only difference i notice flying Economy on US carriers is
- No announcements from flight-deck - not a dicky bird
- Seat belt signs permanently on even on a smooth crossing
- Food sub par
- Cabin crew non existent after first service
- free seat selection on most.
Apart from that Economy is Economy on either and if its going at the time i want at the price I want I couldnt care less.
One of the best flights I had to East coast was on a United 757 half empty.