Well, OK, I'm exaggerating. But I have two roughly similar bikes (Rivendell Atlantis and Rambouillet) that I've set up differently. The Atlantis has 37mm tires, racks, macho touring stuff, and the Rambo uses skinny tires and sort of nods at being light, though I haven't made any effort to prune the last few ounces. The Atlantis has platform pedals with toe clips, because I ride it around town and like to wear ordinary shoes, and the Rambo has clipless Looks.
I've never been able to see much difference in any aspect of performance between clipless pedals and toe clips. So for the last two weeks, just for something to do in winter, I've alternated bikes AND alternated pedals on the bikes, so I've done my normal rides a few times with each combination.
The verdict: No difference. No measurable time or speed difference, no difference in perceived exertion or fatigue, no difference in comfort. If I were racing and needed the last 1 percent of power, I might be able to justify clipless, but for JRA, I don't think it matters.