Xfx vs corsair

I would also go for the XFX, again because it is modular. Another reason why you might choose it over the Corsair is because it has four PCIe connectors as opposed to two for the Corsair, so it is actually possible to run two of some graphics card more easily with the XFX.
 

Which one? There have been three of us saying that the XFX is better than the Corsair because of the modularity.

Obviously you should take a power supply with solid electrical performance over a modular unit that is crap in performance, but when all else is equal modular IS always better.

As for losing efficiency because of modularity I think we would need to see some evidence to be convinced by that.