Certain manufacturers make higher quality PSUs. That doesn't mean none of the other manufacturers make any good ones, it just means they aren't as reliable. It has to do with the way they test and rate their PSUs. Some mislead in their ratings by advertising peak wattage and not continuous. Some also test in temps that promote higher test scores, instead of at normal room temps.
The way they fail can vary greatly. They can just fail quietly and no longer power the system, or they can blow and take some of your hardware with it.
When purchasing a PSU, I look to corsair, antec, pc power & cooling, OCZ, and seasonic. They all make quality PSUs.