From what I can tell getting a good air purify is all about how much air the thing is actually able to move through the filter, which is primary a combination o

From what I can tell getting a good air purify is all about how much air the thing is actually able to move through the filter, which is primary a combination of filter size and the design of the fan itself. At its core, an air purifier is a remarkably simple product. The biggest mistake people make when buying these things is getting something that cannot exchange enough air to keep the room it is in clean. Manufactures contribute to this problem by overstating the square footage their units can cover. With respect to Dyson, I think that their cordless stick vacuums are pretty good, and you can sometimes find good deals on them that can make them not too expensive. They have decent suction that probably compares okay to many low-end corded vacuums, and the battery life is reasonable. If you have only a small area to vacuum, and it is mostly hard floors, the Dyson cordless vacs are a reasonable purchase. Just don't expect them to compare to a decent corded vac in the same price range in terms of power.