I feel that UA has the best service of any US carrier to Europe. 90% of all their equipment to it are 777s. Most of the 777s have PTVs in every class, and all the 767s have PTVs in every class also. In addition, there should be quite a few 777s w/the First Suite.
I've been on AA, DL, NW, and UA to Europe. I've been to London on all of em, and I've been on UA to Zurich in addition. AA is OK, DL is subpar, UA is above average, and NW just bloody awful. All had printed dinner menus except NW. On UA, I received great food with a delicious gourment lemon meringue tart for dessert, and everyone also received gifts from places like the Body Shop, in addition to the free PTV use (whereas on AA you have to pay for PTV on the A300) -- this is all in Economy. I also received steak on United in economy. UA comes around the cabin with hot refresher towels, OJ/Coffee/Water, and candy bars several times throughout the flight. The service is *markedly* different from UA domestic service, BTW. On AA, DL, and especially NW, I didn't find much difference between their domestic and int'l service.
At one time or another, United flew 777s from JFK-SFO, but maybe that's completely arbitrary to the airline. Out of JFK, United only has token domestic and international service. In addition to the most cross country flights out of JFK, United serves NRT daily with 744s (yyay-yeaah), and LHR 3x daily with 767s, Caracas with 757s, San Juan with 757s, and Sao Paulo and Buenos Aires with 777s.
JETPILOT, UA flies 744s from IAD to LHR (1x) and FRA (1x) and from ORD to FRA (1x). UA's 744s are immaculate.
no wire hangers!