Multi-rails being better Is a Myth.....Single rail will not fail you like a Multi rail PSU can.
It's easy.....Look at one If not the Best PSU maker out there...PC Power&Cooling....they refuse to make a Multi-Rail PSU....so there must be something to It.
I only hope that OCZ doesn't crap on them now that they bought them out.
Only time will tell.
Hope It helps.