Serial long-hauler here and this is my advice based on years of experience:
1. Never use a US carrier.
2. Never connect in the US unless it's outbound.
All US carriers suck. They are absolutely terrible - old planes, old grumpy personnel, bad service and forcing you in to their meat-grinding hubs. Their Business Class is like Economy on any of the "new world" carriers. All the seats will still have ash trays - promise.
Since the 9/11 paranoia set in, all incoming US connections have to pick up the luggage and re-check it. This means the whole bloody security rigmarole all over, but worse, once you hit US soil. Shoes, belts, the lot ("Sir, please put your Ipad on a separate tray!!"). No luggage is allowed to check through directly. This adds about 1-2hrs to your connection time on top of the 1-2hrs you'll spend doing immigration and running in endless hub corridors with filthy wall-to-wall carpets. Yeah, that's right - no transit without immigration either. It's a regular occurrence to miss connections when you have 4hrs between flights. I'm not kidding - you have been warned. Miami is the worst, avoid like plague.
My third rule is:
3. Always go direct, if possible. Always. It eliminates all the above problems.
So to sum it up:
a. If you're going to LAX, Air New Zealand is the best, bar none.
b. If you're going to the East Coast, then Virgin Atlantic.
c. Anywhere else, BA....
or
d. ..If you must connect, then there's a fourth neat trick - if you fly Air Canada and connect in Canada, they most often clear you though US immigration on Canadian soil, and you will arrive as a US domestic flight. This saves you about 1-2hrs time. Air Canada not very good in itself, but this is a neat trick.
Last edited by AdamFrisch; 6th Jan 2013 at 18:23.