I'd far rather take a break in the middle and stretch my legs, get some decent food, and breathe two lots of 10-hour-old farts instead of one 20-hour batch. (They don't work like whisky.) It's a little soul-destroying when you board the second leg knowing you have the same thing in front of you again, but it's worth it. And for as long as Finnair Plus continues to award status based on number of flights, the more legs the better
Ultra-long-haul doesn't really appeal to me, even if I could afford to do it in business or first. I'll take the time hit and break up the journey, especially if it's somewhere like SIN (still on my bucket list) or somewhere that a longer stopover is included. Of course, my opinion might well be different if I only had two weeks' paid vacation time.
My friend and I applied for airline jobs in Australia, but they didn't Qantas.