Hi - I would take the Seasonic X series anyday over the other two.
But, if you're willing to pay the $129 plus shipping for the x-650,
then you should get the X-750 for $99.99 & free shipping, limited time of course.
Has anyone had any experience with the Seasonic SS-660XP? It is platinum and 660W
No - I don't with the ss 660 - but it's replacing the x650 which I have and works like a charm.
Really nice the fan only runs when needed.
If I'm purch a PSU for myself it'll be a Seasonic, even tho there a several other top shelf brands.