Im not obsessed with filtration
The fact remains, the nastiest vacuum to rebuild is a Rainbow, they are always full of dirt, the cleanest is a Filter Queen with AirWay and Electrolux right behind, A Hoover Handisac filters as good as ANYTHING ever invented, therefore I use them in all my Uprights, I bought up all of them I could find years ago, and you can re use them many times, but it doesent bother me a bit to use a cloth bag Kirby, yes it will puff a little dust if you rub it against something, but that's no big deal to me,John is exactly right, a Hoover upright of the old school variety will literally run forever and outclean all the Dysons and other so called vacuums made in the last 25 years.