They are pretty much the best choice if travelling transatlantic regularly in cheap seats as you get to premier quite quick and then have access to economy plus. If an infrequent traveller then in general no worse or better than the rest, but with United you have a chance of getting economy plus at checkin which is a positive. You have to pay for booze, tv screens at each seat, channel 9 (live ATC) can be interesting. Depends if you like non-stop, virgin and bmi fly to vegas non-stop.