Custom systems use better parts that have a lower failure rate. Most hardware bugs are issues with the development of the name brand system getting rushed out the door built with the cheapest components. If you're lucky, the company will eventually send you a software patch sometime down the road.
SEO is an ever-evolving game of cat and mouse. Sure, the tactics used change, but the goal of upping your rankings is constant, and achieving that goal is often like trying to catch a tiny, quickly moving mouse.