I will have to disagree with Tolivac about airflow. My Royal 8300 has more airflow than my Sentria. I have measured this by putting my Baird meter at the end of the hose of both machines (my Royal has the optional Hose with attachments). My Sentria pulls about an 8 on the Baird, but my Royal pulls about a 9.5. Keep in mind that I am talking about my 10 amp 8300. Royals with motors smaller than 9 amps will not outclean a Sentria.
If you don't have a Baird meter it's still easy to tell by removing the inner paper or cloth bags from both machines then turn them on and hold your hand about 6 inches away from the fill tube opening. I can easily tell that the Royal has much more air pushing against my hand.
About Royal brushrolls: When I examine the contents of my Royal's cloth HEPA bag, I can find no carpet fibers at all, just dirt and cat hair. This is because the Royal brushroll has very soft and fine bristles, much softer than The Sentria's fairly stiff bristles. The plastic brush stiffeners on the Royal brushroll act like beater bars, which the Kirby doesn't have. As far as carpet shredding goes, have you ever seen a Hoover Senior or Convertible or a Sanitaire destroy carpet fibers? No. The Royal brushroll acts exactly like the ones in those Hoovers and Sanitaires. Soft bristles and stiffeners do not destroy carpet. You can search the Vacuumland archives and you will not find any posters that say their Royal is shredding or destroying their carpets.
