Your opinion? Consider also the user friendly aspect, like cables flexibility and stuff.
I'd add be quiet! Straight Power 11 there.
Corsair RM-x
and Bitfenix Whisper M cables (they're identical) are notoriously hard to work with, depending on your case you might need to put them in under funky angles to properly hide them, in my case main 24-pin cable still protrudes out of the opening, not that it's a big deal, it still works and i'm not doing a cable rework every week or smth but still if you're nitpicky about such thing then Corsair is probably not for you.
Edit: Bitfenix Whisper M cables are different actually, they have capacitors right on the 24-pin connector hidden by a rubber kind of sheath, and the cable itself is ribbon-style should be way easier to work around than Corsair.
Both Enermax and be quiet! cables are ribbon-style, without in-cable capacitors, should be relatively easy to work with. With be quiet they even have a relatively rare configuration of only one 6+2 PCIe connector per cable, it's a good thing since if you need two 6+2 connectors for your GPU then you should use two separate cables anyway, and such there wouldn't be an odd piece of cable dandling around.
Overall i'd probably still put Corsair RMx over be quiet SP11 if cables are not an issue tho, so :
Corsair RMx > be quiet! Straight Power 11 > Enermax Revoltion DF > Bitfenix Whisper M.
That's considering they have the same price, if any of them is like 10 euro cheaper i'd go with that.