I think some people just don't know how to "use" multi-rail PSU's. AFAIK you've got to know which connections are for which rails. Otherwise you're going to load all your HDD's and your GPU/s through one rail, and the other rails get left doing nothing.
But then, that doesn't explain why my brand new HX650 started ticking the moment I fitted it.
I've never like the multi-rail ones but I always thought it was just a preference of mine. Now I see it as an important choice when I'm choosing a PSU for my rig.