Within Australia now I prefer to fly QANTAS. AN used to be better but I believe the " bottom line " has particularly hit their Businessfirst Class.
In their narrowbodies ( most of domestic fleet except if you are travelling SYD to MEL ) unless you get rows 1 or 2, you are paying a lot of money for a fancy economy class seat ie no one in the middle.
When Domestic First Class was abolished, the ads claimed the new J class was even better. NOT SO !The meals are better than Economy but just. Wines in First were great and now , there is only very cheap sparkling wines and fotgettable reds and whites- you know- the kind you buy at a liquor store for US $5 a bottle.
Service is better than Y but only if you are the front. By the time the FAs get to rows 7 or 8 in Bus First, believe me, you are getting pretty hungry and thirsty!
Even being Star Gold and being full fare hasn't always guaranteed me a seat at the front.
My most recent experiences with QANTAS have been more positive. ( even though they have also removed their F class )Beverages are much higher standard and meals served much faster and aircraft not so shabby.
In short, Unless someone else is paying, I don't travel J class in Oz. If I did, QF would be my first choice.