Lily producers, such as B&D Lilies, have actually stopped producing the Golden Stargazer because this one is so much better in color and stature

I still adore Golden Stargazer.

So do I, but I'm curious to see what BellaDonna looks like next to Golden StarGazer.

I think they are very different flowers. 'Belladonna' has a larger, different color of yellow flower. They are both nice, having grown both of them.

Do you have any idea why one of the growers thinks that the Belladonna is better?

Larger flower, possible better disease resistance. Haven't had any problem with it falling to virus in the many years I have had it. Different people have different experiences with different things. Seems like I had heard it was more prone to virus, it just hasn't been my personal experience.

Some of the "new improved" lilies haven't done well here. So perhaps it's a little bit of trying to buy what you like, seeing how it does for you and evaluating your own space. But most of all, enjoying every minute of it.