There's more than a few variables in dust collecting that determine how effective they are. Cloth bags with 5 micron or greater filtration allow the finer dust to get back into the shop air.... better than none at all, but not the most efficient. There are bags that will filter down to 1 micron ..Amazon has them, if I recall. Cannister filters are more expensive than bags, but way more efficient....more surface area and finer filtration.I see rockler has the dc-650 bk on sale and was thinking about it. I don't have a dc unit right now and it seems like a good deal. Just wondering if anyone else has used this model. My shop is in the basement in a 11x22 room so noise is a factor.