The Sharper Image Ionic Breeze 2.0 is for small spaces, like your bathroom. We have found that this small unit is very effective in eliminating odors in our bathroom. The unit does collect dust on the stainless steel chamber, but I can not tell if it makes a difference in collecting dust in the room.
I like that it does not require any filters and is easy to clean. You just pull the inside chamber/blade out and wipe it with a damp cloth. You then turn your unit upside down, once or twice, and plug it back in. It plugs into any outlet. Do not put the chamber back in while it is damp. Give it a couple of minutes to dry off.
This unit is also silent, but if a lot of dust is on the chamber/blade it will start to make a noise. Cleaning it will take care of this. We clean the blades about once a week, sometimes every other week.