Power Supply Units (PSUs) have always been one of the most failure prone components in a PC. This is often due to the fact that the units included with pre-built systems usually emphasize cost over quality and performance. As a guide, here are some of the features I look for in a PSU, which are generally indicative of high quality, high performance units:
Other features to consider include fan noise, modular connectors, sleeved wiring, etc.
Brands that I often recommend including these features are PC Power & Cooling
power supplies. Both of those companies feature single-rail designs
which are primarly manufactured by Seasonic