With my current competition gear, my bullets face forward and I use the index finger on the bullet side of the magazine method. That being said, I don't think bullets facing the rear should be considered incorrect. The conventional wisdom of "majority rules" doesn't mean it will work for the individual. What if that person has arthritis or an injury that limits their range of motion, for example? The other issue is we're talking about bullets forward with a shallow pouch, on the hip, that allows you to get a full grip on the magazine. Not everyone is going to have that setup (IWB conceal, MOLLE mag pouch, pants pocket carry).
This is an ergonomics argument that's almost impossible to fully explain in words, but i think if you're trying to factor in the amount of twist in the hands, the magazine, and the fingers, it's really a wash between the two methods.
Anyone have any videos and stopwatches?