No need to read that, just buy Seasonic SS series that fits your budget. If not, well buggers, you ain't going to have good PSU in your PC. Rest are a bit crappy. If your PC isn't draining lot of power, then you can get 420W from Seasonic. But if you use high end components, then you should have money for high end PSU.
Edit: Mistake, meant SS series. S is bronze model, decent but not excellent. Still if you can't buy SS go for Seasonic S bronze. Do not buy CM, Corsair, Evga and other shit. Antec and Enermax are good too but not better than SS and think they are more expensive. There are ultra high models costing 300+ dollars (Targa manufacturer) but you don't need that...