I would imagine there is some improvement but, would you bother with a $110 bag for a $125 DC. My little Delta 1HP has performed admirably although it is overworked. I was planning on a Dust Gorilla but the price increase has me thinking of another solution (the shock will probably wear off).
In the meantime I was thinking of adding a custom bag from American Fabrics that will quadruple my filter area and bring me a finer filter than the OEM bags. Has anyone here tried these and are you glad? Do you wish you'd just waited another year and gotten a cyclone?