500 to 350

This new Link version, also $500 and £350, promises all of the same air-cleaning features, but in a first for Dyson, it also tacks on a related app for Android and iPhone users. With Dyson's Link app, you're supposed to be able to check in on indoor and outdoor air quality at a glance. But the real standout feature is that the Link app is designed to use that pollutant data to automatically tweak the settings on the Pure Cool Link purifier to perform optimally. (Dyson's 360 Eye robot vacuum is also supposed to work with the Link app when it goes on sale later this year.)