The will preform the same, they have the same dimensions. There are a few factors that make up the price difference. The setrab cores have female fittings on them so we need to include adapters for a male -10. The mocal coolers have the male -10 fittings built into them. I believe setrab recently raised their prices. In the past the mocal and setrab coolers were approximately the same price.
BTW, orbital we will be offering a single 25 row kit in the near future for all your automatic needs
-Dan