The "stock" 480 is the PCB and cooler design shared by all reference cards, regardless of manufacturer, and designed by AMD. Most manufacturers will have their own custom designed cards where the GPU chip is the same but other aspects can vary, such as slight clock speed changes, different PCB layout, VRM design, and cooler design. As a result some cards will overclock better, run quieter or cooler, or have slightly different factory overclocks. Then of course you have to consider the brand itself in case you need to mess with their warranty or customer service.