Anyone quit flying Delta 17 or 16 because of quality of service?

I fly DL 17/16 about 5-6 times a year, I’ve done it in BE and Coach and it doesn’t seem to make any difference, I get more and more frustrated at Delta each time I fly.

Saturday I flew PIT-ATL-LAX-SYD-BNE and it was the worst flying experience of my life. I’m starting to expand my horizon since I’ll be based on and off in BNE so ditching the LAX-SYD route may be a good idea since Delta 17/16 service isn’t my favorite (not to mention the PITA of switching terminals in SYD). Going home I’m booked on VA 7 from BNE-LAX next week to give it a try.

I’m in PIT so I can short hop to JFK so I have quite a few options, these would be primarily biz class

Out of these routes and airlines what do you suggest I should prioritize and try first?

Korean Air, PIT- JFK-ICN-BNE
Virgin Australia- PIT-MSP-LAX-BNE
China Airlines, PIT-JFK-TPE-BNE
China Eastern: PIT-JFK-PVG-SYD-BNE
Asiana Airlines- PIT-JFK-ICN-BNE(Korean Air)
China Southern: PIT-MSP-LAX-CAN-BNE (Cheapest Biz Fare)