I actually like that BikeRadar article and think it's good.
Note that in that article, they notice that the real-world data is more finicky than the reliable wind tunnel. It's very plausible that those nice 31 watts you see in the wind tunnel are significantly decreased with the variations you see outdoors, hence the need for wind tunnels for measurement.
I know people with multiple bikes. Like an older aluminum framed, wheels Specialized that weighs 22lbs and then a 2012 Trek carbon bike, carbon wheels, Ultegra and we ride together about once a week. There is no real difference I can tell in his speed or endurance. Same goes for my friend who sometimes rides a Cervelo P3 Dura Ace set up and sometimes a 27 yr old Specialized road bike, also Dura Ace. Again, he says the Cervelo accelerates faster and is soother riding, but not as comfortable, but either way his performance is not really much different