There several things to consider when buying parts from these companies.First is the gauge of the metal part, 16 or 18 gauge then the fit of these parts. I have used both Brothers and the Truck and Car Shop over the years and both put out a quality products. Their patch panels are 16 ga. just like GM. orginals. Early Classic Enterprizes is another company who puts out quality parts for the 60's thru 70's trucks too. I can personaly vouch for these guys as I have never had to return a part back other than shipment damage.
I am sure that the other companies have quality parts too as they would not be in business this long.
62Blue
Don