Here's an article on the advantages of HEPA filtered backpack vacuums. In particular, it deals with the disadvantages of using treated dust mops on hard surface floors, particularly floors with a finish. Besides the gummy debris that dust mops leave in corners and along edges, the dust mop treatment (and one really needs use treatment on the dust-mop, to better contain the dust) impacts the floor finish, generally yellowing it, leading to more frequent stripping and refinishing - costly in time, environmental impact and, well, cost.
The article also touches on the health impacts of leaving fine particles behind (including allergens and bacteria), a result of both dust-mopping and vacuuming with a less-than-HEPA filter on the vacuum.
We go a step further. Figuring that we likely cannot improve what we cannot measure, we regularly measure the dust (airborne particle count) carried in the air within our clients' facilities. In general, as compared to standard unfiltered vacuums, dust-mops and feather dusters, we find we can achieve about a 50% reduction of daytime airborne particles, in the size range of most allergens. So our client inhales less gunk.
Not a bad deal for a small investment in vacuum filters.