Pva presentation (also found in packing) foam will stop tangles, only problem with using it with braid is that the bait will drop right on the lead after the foam has melted, so a coated braid hooklink is better as the bait is kicked away from the lead after melting.
They sound like a bit of a gimmick to me, but if they are the same price as anyone elses swivels then why not have ones with bearings in them. If they are more expensive, then I wouldn't bother, because I get on fine with most swivels.
Can anyone show me, with diagrams etc..., how to splice leadcore? I have seen instructions before in a mag but I don't know if I was reading it right, but the loop that was made couldn't possibly be strong enough to hold a fish on.