One of the main reasons North American Eureka uprights cleaned better than Hoover uprights in the 1960's and 1970's was Eureka's use of their wonderful top fill "Style F&G" disposable dust bags.
Air flow was better maintained in these Eureka upright bags because the dirt fell away from the air path at the top of the bag and never blocked it. With bottom fill bags, every time you start up the upright vac, you kick up whatever dirt is sitting at the bottom and you send a dirty stream of air up into the rest of bag, causing faster clogging of the tiny bag pores when compared to top fill bags. The fact that Hoover changed over to top fill bags in the 1980's signifies that the company realized this system is better.
