all are tier 1 PSU i think the EVGA G2 is the cheapest among them and gives 10 years of warranty plus made by super flower one of the best PSU manufacturer so you can go with it.
EVGA G2 750W , XFX 750W Pro Black Editon , Seasonic X- series tends to have coil whine.
Evga B2 , G2 , P2 , T2 are the best power supplies on the market.
Ther first sentence you said, to clarify, all 3 have coil whine or just the Seasonic?
Also, what model EVGA is most high end? B2, G2, P2, or T2?
Since your a PSU Master, I thought you would know