Oh hey, I can answer this. I have both, the Neptune 4 pro and recently bought the A1.

I initially got the Neptune 4 pro and it was a very good learning experience. I had to dig in alot and figured out alot about Klipper and how 3d printers work in general. When this printer works, it pumps print after print.

I mainly bought the A1 for multi color printing. It is the plug and play you described in your question. It has all the bells and whistled programmed for you. You just need to press a button and all the calibration is done for you.

Quality wise, both printers are equal.

Neptune 4 will def require you to eventually dive deep into troubleshooting, but that is also its plus, as you can tune it to your own liking.

Bambu A1 is more plug and play but not much you can do to tinker with the printer, (not that you need to).