I live with a smoker and 2 dogs who are prolific shedders.  II have larger air purifiers in the  larger rooms of my home, but they are SO loud- even on the lower "quiet" setting.  I wanted something smaller for the office and bedroom, so I chose this one and got 2 of them.  They're quiet- I don't even have to shut them off to take a phone call. 
I love that they are streamlined and can be used ether vertical or horizontal to fit any space, and that the filters can be vacuumed.  Have you seen the price of replacement filters for other purifiers?  This one is definitely the way to go!