Just purchased two Fit 50s to complement my Breathe Smart which now nearly cover my two story home. Fit 50 is very compact and EXTREMELY QUIET compared with the larger unit. All of the units do a remarkable job removing dust, which was my main consideration. Upgraded one of the Fit 50 filters to the HEPA Odor Cell.....uncertain it removes odors at this point, but, worth a try in my estimation. Overall, I am very satisfied with Alen products and may add one more to finish the project. Also, I spoke with Stephen @ Alen Customer Service who was informative and able to tailor my needs better than ordering directly from the website.