Looking at doing another LAX-BKK trip and I am quite confused about which carrier/routing to use.

On most days, the cheapest route is with one of the 4 Chinese carriers out of LAX. These are China Southern (via CAN), China Eastern (via PVG), Air China (via PEK) and China Airlines (via TPE). Each connects in a different city. I have done China Eastern via Shanghai and Air China via Beijing, but am wondering whether any other carriers would offer a better or more reliable connection.

Not too much to do on a 4 hour connection in PVG or PEK.

Of course, United or JAL, would be my preferred choice via NRT, but this is usually the most expensive.

BTW: Only 1 out of 8 flights on China Eastern credited anything to my DL Skymiles account due to the low fare bucket.

Thanks in advance for any advice.
Regards, Max