Last week i conducted a very unscientific experiment with my bs36 and the wifes dyson dc07 on our living room carpet, a 50 ounce wool twist laid that day and obviously shedding fibres like mad, vacuuming in 4 directions, the sebo managed to go over it in 2 directions before the bag was 3/4 full, the dyson (which went after the sebo)didnt manage to complete the first direction before needing emptying, to complete the 4 passes the sebo used 2 bags, the dc07 was emptied 4 times and was half full on finishing, not exactly lab conditions i know but it proved my suspicians,the only advantage i can see in using the sebo in a customers house is that they are a lot less likely to have one sitting in the cupboard.