AMD certification certainly says something for how it will perform when you get it. However all bets are off on how it will perform a couple months from now. Reliability and noise are going to be the big differences between this and say an Enermax, PCP&C, or Antec (shut up Hagbard). Also the only thing that the (the way I understand it) AMD certification deals with is the number of AMPs that the power supply can pump out, it doesn't deal with ripple or anything else that could potentially affect stability.
Eric