It will take a well designed robot "cyclist" capable of mimicking human pedaling characteristics to settle the debate over eccentric chainrings. It'll need to be able to apply consistent power while also mimicking hitches in gait, differences in leg length, etc.
Otherwise our anecdotes are just that. My power output varies so much from day to day that I can't attribute much of anything specifically to the bike or components.
My theory is that eccentric chainrings feel better to those of us with flawed pedaling styles, often due to injury or imperfections in skeleton and musculature. I seem to do better with the smaller 42T Biopace chainring, while the 52T Biopace doesn't feel like it does much -- probably because the larger ring isn't much out of round. It would be interesting to try an eccentric ring smaller than 42T, especially for climbing. A new-to-me older bike I'm building up may give me that opportunity.
And watching Chris Froome reinforces my theory that eccentric chainrings favor imperfect pedaling. Froome does almost everything wrong on a bike. He looks like a pterodactyl that swooped out of the sky, ripped the skin off a human and put it on as a disguise, then stole a bike and started racing. Ungainly and awkward don't quite describe his style. And his bike fit is all over the place. In the course of a three week grand tour he'll change his saddle height almost daily, sometimes looking like his knees are about to strike his chin. His bike handling is among the worst in the peloton. But he has that incredible engine to compensate for the flaws.
And he's still more graceful looking on a bike than I am.
So if it works for Froome, it couldn't do me any harm.