I would buy a "new" 100% compatible Amiga 1200, since maintaining old ones is a chore, but I never had a C64 so not really into that.
I think it’s more down to what was your first computer at the time. Those who had the Amiga first would argue that the C64 is not what they would want.
My first Commodore machine was the VIC-20. I never got to own a C64, the next machine after the VIC was the Speccy 16k, the. The A500 Amiga.
Only fairly recently I took the plunge bought a C128D, which now I see what the fuss was about.
Would I buy one of the new C64s? More likely not.
As for the debate about, “Well Amiga and Commodore are separate”. You can argue, that without Commodore buying the Amiga brand and distributing etc… Would it have been as popular?