well biked

I don't think it does at all. Keep in mind the link is to a company's website that makes bearings with loose balls, and touts them as being able to carry a greater load because of it, axial or radial. And again, why would Shimano make hubs with loose balls if they didn't feel like there are performance advantages? Are the retainers in the Dura Ace wheelsets, the ones kleng describes as being kind of like a netting and nothing like the old tin retainers that are most commonly seen on bikes, designed in such a way that they do create some advantages? I think they probably are, but I seriously doubt that all retainers are created equally in terms of enhancing performance, and that these netting-like retainers on the Dura Ace wheelsets are worlds better than a retainer you'd typically see in a bicycle bearing.

So if you're saying that these netting-like retainers (and probably the ones on the Campy hubs, too) on these high quality hubs create some performance advantage, I agree that the answer is probably yes. But if you're saying that a bearing on a bicycle with the balls retained in a typical tin cage is better than loose balls, I disagree.

Btw, apparently the only hubs Shimano makes with the retainers are on the Dura Ace wheelsets and the Dura Ace front hubs, model B. All of their other hubs use loose balls, including the Dura Ace "model A" front hubs, and the rear Dura Ace hubs-