i use the brush bar as we don't have carpets, just tiled floors, and normally all the dog hair gets sucked up into the cylinder just fine - the amount of hair she sheds is astounding and i vacuum and empty the cylinder every day, and the Dyson is handling it really well... the past couple of weeks have been tougher as she's been moulting, shedding huge chunks of hair despite brushing, and some hair did get wrapped around the little wheels on the side of the brush bar for the first time, but didn't get caught in the brush itself - the brush/roller bar is really easy to dismantle and clean - i've found the main problem is mine and my daughter's very long hair (past waist length) - now that
does get wrapped in the roller brush - it is an absolute pain! and i have to dismantle and unravel every time! we're worse than the dog for shedding i think lol!
ps- there is also another attachment without a brush which might be for carpets?? but i use that on the settee and it works really well with the dog hair too, and no brushes to worry about...