as noted above, you have to go model by model. most brands sell really good units and some junk ones as well.
you got to check out some reviews to see what is worth it or not. there are a handful of companies that actually make psu's. everyone else slaps their label on it. based on what they want the unit to cost, they pick and chose options to include. thus some end up very poor psu's, while some end up really good ones.
seasonic, super flower, CWT are some of the main psu makers. most everyone else just puts their label on what they contract them to make.