I bought one of each of the following: Borgwarner / Niehoff , AC Delco / Wells , Wells Gold /Duralast Gold
AC Delco is the OEM supplier. Wells standard line is less expensive and an exact duplicate of the stock AC Delco parts. The cap is black with steel contacts.
Delco part #D465 rotor $14.40 , D328A cap $43.76 (list price) total: $58.16
Borgwarner is the premium line, however the Niehoff Ultra is an exact duplicate. These caps are colored light gray, and have a white rotor. The contacts are brass.
Niehoff part #DR58K rotor $10.99 , DR79W cap $29.99 total: $40.98
Wells Gold / Duralast Gold are the same parts just different packaging. The cap and rotor are dark gray, with brass contacts.
Kit part # DR2030G total: $52.99
I have said that the rotors are the clincher , and this is still true in this case.
Rotor: The AC Delco rotor is the best design , IMO. It uses two pins and a capture block to retain the contact. The Niehoff rotor is an exact match!

Cap: Of the three caps brass is a desirable contact. The Niehoff cap has much better refined contacts. The Wells / Duralast Gold caps contacts appear to have been "snipped" or shear cut. I am not comfortable with the integrity of alignment, or "true" , using this method. They also show signs of marking or marring during manufacture.
The Niehoff contacts appear to be machined and are smooth. Nice looking!
Fit and finish of the Niehoff parts is obviously better than any of the parts examined. They lack stray flashing, plastic is heavier in reinforcement webbing, mounting surfaces are smooth and square. I had checked their rotors in the past, and obviously they have stepped up with some improvements

All examined did come with thread locking compound on the screws. The Niehoff had red locking compound, I am not sure if it really differs, but we all know to buff it all off before installation. ( See warning: Plastic Distributor )
Summary:Niehoff part #DR58K rotor and DR79W cap $45.98. Best price, best design, best choice , and the ones I will be using.

Now off to return some parts
