Originally Posted by Unoriginal Sin
they're not the only ones to produce brilliant
units which easily rival and/or outclass Seasonic's efforts
I hope to not going too far in OT territory, but I think it's questionable (and why didn't you mention Zippy?): IMO "outclassing" is a severe word.
I'm not a PSU expert but as many web readers I'm used to trust a bit what Oklahoma Wolf finds about PSUs, and all I can say from his tests about your statements is that usually Delta excels in ripple suppression, SuperFlower in efficiency, Seasonic in voltage regulation.
For each OEM the other performance (of coeve similary priced units) are indeed very often quite consistent with each other, IIRC.
I mean, if 1% of more efficiency at a given power level, or 0,1% in ripple suppression - or half a point in a JonnyGuru review, to come to my favourite readings - can make any real difference, well, my PCs never have been noticed of: and personally I would never call such a difference as an "outclassing".
I don't own any Kingwin units, as here there's almost no way to buy them, but currently among my PSUs I have 1 Antec Signature 650, 1 Seasonic X-750, 1 Antec HCP850 - which replaced a former Antec CP-850 - and 1 Seasonic M12D 850.
Summarizing, FWIW the X-platform (Seasonic, Corsair, XFX...) is a very good all around, currently not "outclassed" - in the above quoted personal meaning/reasoning - by any similary priced 80plus Gold unit. IME (but maybe I'm biased 'cause they're always among the quietest, at those power levels I'm used to).