A:Answer I have only owned it a couple weeks, but I used it the first day on some carpeted stairs that had not been properly vacuumed for some time. The small hand attachment with the non-Zero M beater bar got completely locked up with hair on the first step, within a minute. I switched to the main beater bar head instead (heavier and harder to maneuver in the crevices of the stairs), and did the remaining 14 steps without getting tangled. Afterwards, the main beater bar had some hair on it, but after vacuuming the living room, all of it was gone. So yes, I'd say the Zero M feature works amazingly well.
Sorry to get off topic and on my soapbox, but emptying a bagless vacuum SUCKS. It's a nasty, dirty mess, which can not be done in the house, no matter how the cup is constructed and no matter how you do it. If Shark would make this with all the features it has but with bags instead, I would gladly pay another $100 for it, and put up with the added weight. I don't understand how people value saving $2 on a bag every few months over the mess of unloading a dirt cup every week.