Hi John,
I don't know what others think, but I can pass this along. About 40 years ago a company had a booth at the Texas State Fair where they sold these and they had a demonstration using a small (maybe 10 inch) wheel and tire that was spun with and without the beads so you could see how effective they were. The beads were in a clear plastic tube with some clear oil in it which was attached to the front of the wheel rim so you could watch the things re-orienting themselves as the wheel spun. As it spun (fast, I'll add) the machine spinning it became smoother until finally it was almost perfectly smooth. After a year or two the company had to stop selling them. The Fair investigators from what I was told concluded it was a bunko game. What I remember was (a) these work best on large wheels/tires (which aren't easy to balance and require special equipment) and also on pretty small wheels/tires. They weren't always effective on common size wheels and tires...hence the complaints to the State Fair folks. (b) at slow speeds they do nothing...they must be spun above a certain speed in order to work at all. (c) once you install them if you want to remove them it isn't always that easy to get them all out and all of them must be removed or the wheel/tire can't be balanced using common equipment and ordinary weights...that being the beads will work against common weights and spin balancing systems will be given the wrong input while the beads are moving so you'll only achieve balance at one speed...the speed of the spin balancer. Any other speed will be out of balance until the beads are all gone. Whether these are the same as the things being sold today or not I can't say but in the early 80s they were pretty much of a mess down here. Hopefully things have improved.
