A couple of years I remember such a discussion at work, where I was evidently a lone holdout for cannister with a bag, everyone else opting for bagless uprights. I like being able to vacuum under things, like beds, short tables and such, which you can't do with most uprights unless you hook up a hose of some sort. The main reason is that considering what you're concentrating; dirt, skin, dried up nose buggers, dog hair, dust mites, dried pulverized doo doo, spider eggs, week old pulverized bits of chunky turkey dog food, etc., do you really want to create a cloud of the stuff and breathe it in when you dump it ? I prefer that it stays in the bag when I dump it.