Qantas' re-entry onto the Sydney-San Francisco route has broken a monopoly enjoyed by United Airlines for the past few years, and also made it more appealing for travellers to Fog City to fly direct rather than make a time-consuming stopover at LAX.
But United hasn't taken anything for granted, with the US carrier and Star Alliance member rolling out its Boeing 787-9 Dreamliner to deliver a superior ride on the 13-hour trans-Pacific trek.
With just two airlines on this route it's a clear-cut either/or decision: so how do the business class travel experiences of Qantas and United Airlines compare?
Qantas flies Sydney-San Francisco (QF73/74) six days a week, skipping Tuesdays.
United Airlines has locked down a daily slot for its UA870/863 service – providing the daily frequency which business travellers prefer in order to plan their schedule with maximum flexibility.
Qantas QF73 leaves Sydney at 1.30pm to reach San Francisco around 9.30am.
United has opted for an earlier run, with UA870 wheels-up from at 10.30am for a 7am arrival into San Francisco which also dovetails into United's schedule for connecting flights out of its San Francisco hub to the rest of the USA.
Qantas enjoys a natural advantage here, with Sydney being the Flying Kangaroo's home port – and where you'd expect to find its flagship lounges.
It's true that after almost a decade of solid use, the Qantas International Business Lounge is in serious need of an upgrade.
But the variety and quality of meals, drinks and service are outstanding for a business class lounge, and flyers on QF73 out of Sydney can sample fresh juices as well as gelato made in the lounge's own kitchen.
United's business class passengers out of Sydney have a choice between the lounges of Star Alliance partners Air New Zealand and Singapore Airlines.
United steers you to the crowded Air New Zealand lounge where there's barista-pulled coffee, an 'egg station' for poached or fried eggs cooked to order plus the usual scrambled eggs, baked beans and grilled tomatoes.
AusBT review: Air New Zealand lounge, Sydney Airport
However your business class boarding pass also opens the doors at the neighbouring Singapore Airlines lounge which is less crowded and has a much broader range of dishes from the traditional Western breakfast to antipasto, smoked salmon, frittatas, chicken congee and lasagne.
Our tip: visit the AirNZ lounge for the coffee and the Singapore Airlines lounge for the rest of your breakfast.
The winner here, however, is clearly Qantas – at least for your outbound Sydney leg of the journey.
When you're flying back from San Francisco both airlines serve up a sadly sub-par lounge experience.
Qantas relegates all but its VIP frequent flyers to the decidedly average Air France Lounge instead of the excellent Cathay Pacific lounge, which turns away most Qantas travellers despite being part of the same Oneworld airline alliance.
United's SFO lounge clearly expects you to dine in the air, with only soup, salad and snacks on offer.
Savvy flyers head next door into the lounge of Star Alliance member EVA Air for a superior spread of Chinese dishes.
Qantas flies a Boeing 747-400 on the SYD-SFO route. She may be the venerable 'Queen of the Skies' but despite an interior refresh she's showing her age.
United has upgraded all its Australian flights to the very latest Boeing 787 Dreamliner, which aces the jumbo in every way.
The Dreamliner is significantly quieter, has a modern spacious cabin and even flies smoother.
More importantly for passengers, higher humidity in the cabin, cleaner air filtration and a lower effective altitude than the 747 makes the flight more comfortable and reduces the effect of flight fatigue and even jetlag.
You'll step off your United flight at San Francisco feeling fresher, more awake and alert, and ready to stride into your first meeting or presentation.
Both Qantas and United are out of step with the latest in business class seat design.
On the Sydney-San Francisco route Qantas and United fly seats arranged in pairs...
... although United edges the Red Roo by providing a little more room to keep your carry-on kit close at hand.
At least both seats convert into a fully-flat bed for the 14-hour flight.
And speaking of sleep: although almost the same width, the Qantas' Skybed II feels noticeably wider in bed mode than its United counterpart.
It's also a better snooze experience: Qantas dresses the seat with a mattress to flatten out the bumps, provides a quilted duvet cover and a pair of cotton pyjamas.
With United you get just a pillow and a blanket. But if you're a light sleeper who can do without those creature comforts, then the quieter and less tiring ride of United's Boeing 787 is a better choice.
American airlines in general don't exactly knock the ball out of the park when it comes to in-flight meals. Even in business class the food is 'good' rather than 'great'.
United sticks to the basics with mains: choose between beef, chicken, fish or pasta – while breakfast is cereal or an omelette.
Qantas' association with Neil Perry's Rockpool Group yields much better fare, from small plates to mains bolstered by soups, salads and sandwiches, plus a more extensive wine list.
Work and play
The benefits of flying a modern jet like the Boeing 787 again works in United's favour.
There's inflight Internet which runs at a useable clip and costs just $US17 ($23) for the entire flight without any data limit.
You also get a much larger personal video screen, at 39cm against Qantas' 30cm panel (both airlines' libraries of movies and TV shows have more than enough to please passengers on the trans-Pacific trek).
And the winner is…
Which airline makes the best play for your Sydney-San Francisco business travel budget?
All things considered, it's surprisingly close and depends on which factors you prioritise: Qantas wins for lounges and inflight dining but United's modern Boeing 787 makes the 'core' experience of the flight a far better proposition.
Also read: How to buy a San Francisco Clipper card
David Flynn travelled to San Francisco as a guest of Qantas and United Airlines.