I still love my LX and LXI machines, and they both work wonderfully well. As a point of reference the Electrolux did use an after filters through the Automatic E.
There is a rubber collar/seal around the inlet tube that presses up against the cardboard to seal the bag and yes you will see some dirt and dust around this collar but it shouldn't leak into the bag chamber.
I'm also finding packages of genuine Aerus and Electrolux bags at Goodwill all the time. I've also see the generic bags there too. You can usually pick them up for a dollar or two.
