The Achilles heel in every vacuum since the dawn of electricity has been the dirt removal/filtration dichotomy. Increase one, decrase the other, with a few notable exceptions-water filtration machines (with a separator and an electric power head) the Airway and Electrolux multi-layer bags, and now the 3M filtrete bags. No, they are not perfect, but they are a vast improvement over any other cloth/paper filtration system. More dust trapped with higher airflow over a longer period of time, that is the goal.
Dyson and Rainbow (Hyla-et al) are beating a dead horse. They keep comparing their filtration systems to the most popular, (not always the best) competition AT THE TIME OF THEIR INVENTION.
Over sixty years ago Electrolux and Airway figured out that multiple-layer bags gave better cleaning and filtration over longer periods of time, and 3M filtrete is the next logical step in the advancement of that technology. Older cloth bag vacuums leaked, but in light of the quality of air with coal burning factories, tanneries, meat packing and rendering plants, the vacuum was a quantuum jump in cleanliness. But today, bagless hepa is an oxymoron, like 'military intelligence'. If you need the standard of hepa filtration to avoid going to the ER with an asthma attack, what are you doing with wall2wall carpet in your home anyway? The person who is thus afflicted should not be vacuuming, EXCEPT with a central vac, or a Miele canister, or something like a Rainbow. Alas, Airway is no longer with us.
Once the filtration is determined to be satisfactory, issues of nozzle design, user friendliness, type and quantity of soil to be removed all come into play. Filtration is one of the primary considerations, but, if a vacuum cannot pick up the dirt, it cannot filter it. A 100.00 bagged Big Box vac with proper and frequent enough use and maintenance will do a respectable job of removing a buildup of dirt and keeping it at bay. Every vacuum needs maintenance. A 100.00 Dirt Devil and a 2000.00 Kirby both need bag and belt changes and the roller brushes cleaned to perform at optimum efficiency. This is how and why the purchaser of an expensive vacuum (name your brand) can be sold another of the same, or a different, brand just a few years later: infrequent use, improper use, and neglect of the three B's (bag,belt,brush). Allergy symptoms will be drastically reduced with any vacuum provided the buildup of dirt in the home is removed and kept from accumulating. Less dirt = reduced symptoms. I have seen the customer's vacuum emerge victorious, not often, but often enough to prove the point that frequent use, proper use, and appropriate maintenance are more important that the brand of vacuum one owns, cheap big box bagless units notwithstanding.
