Is there a really big difference in cleaning performance?
It all depends on the brand and model of vacuum cleaner you are talking about.
Vacuum cleaner manufacturers have made great strides to design a brushroll w/o a beater bar that would create results close to a brushroll/agitator w/a beater bar. They have added brush stiffeners or brushes w/different degrees of stiffness. Different brush lengths also play a factor.
Vacuum users wanted to use their uprights to clean their floors. The only problem was, they did not know how to use the vacuum cleaner properly. Example, they would lower the height of the upright to the lowest setting; causing the beater bar to knock against the floor. Or, they would run the vacuum over those metal thresholds. Boy, what noise that makes. Vacuum makers, who made agitators w/beater bars slowly started making agitator w/o beater bars. The main players for the change were Eureka and HOOVER.
There is no fact that beater bars damage or flatten carpeting. It does not matter what height the vacuum is set at, it will not flatten it. While the beater bar goes by hitting the carpeting, pushing the fibers away from the brushroll/agitator. The fibers then snap back up. Plus the brushstrip follows; lifting the nap into place. HOOVER created the beater bar in 1926 with its principle of "positive agitation". Even before the invention of the beater bar, competitors of HOOVER "badmouthed" them saying that HOOVER machines damaged carpeting. This, of course, was not true, because carpeting actually looked better.
Even in the distant past, some vacuum cleaner salesmen like Kirby salesmen would promote their beaterless brushroll as better, because it does not destroy carpeting like a vacuum cleaner w/a beater bar would. There is one point that I will make and that is that there is an instance when a beater bar will/could damage carpeting. If a plastic beater bar is gouged or a nail gets caught in the bar, then that could then cause damage to carpeting.
HOOVER continues to top the list for very good carpet cleaning, even w/o a beater bar. Matsus-h-ita and Tacony Corp. also have very good brushrolls.
This message was modified Nov 1, 2007 by Mike_W