AC-Delco doesn't MAKE anything any more. They're a sales organization, not a manufacturing organization. They sell whatever their subcontractors provide.
Standard used to be among the best aftermarket parts. Now they offshore too much stuff.
Far as I know, Standard and BWD are owned by the same parent company.
I would look for the "Made In USA" tag on the packaging, and buy whichever brand has that label. If none of them do, Standard, Delco, BWD, Echlin...all about the same quality.
Some folks are really hot for Wells. I always thought of them as a "second" line, but that was before everyone was just reboxing the same parts.