Best Filtering vs. Best Value
For better filtering, I like Sanitaire F&G allergy filtration bags. The Eureka "Filteraire" bags also seem to do well. I use Sanitaire bags in my F&G machine at home. At work I run cheap F&G bags in my two vacuums. Right now, I'm using the basic Eureka branded bags, though I've also used Envirocare bags in those machines as well. I picked up 20 Eureka brand F&G bags for $15 at Amazon, which at $0.75 per bag is a reasonable cost for bags that I quickly use and dispose of at work. Not much use in ponying up for allergy filtration bags that cost $2.00 per bag at work, as the clay dust tracked in by the students tends to block my bags up rather quickly.