Needed two of this size to cover the entire living area. Blueair's sale allowed me to afford both units. These units blend right into our design so they're hardly noticeable and extremely quiet on lower settings. The automatic feature takes any of my involvement out of the equation. Plug & play and go about your business. Filters are expensive and trust they and the sensors work but haven't noticed any odors and my independent air quality sensor tells me the air is "excellent".

As a more expensive unit, I had high expectations of the Pro XL. It meet all of them. (I live in smoke filled Northern CA and use the smoke stop filters.)

I also own a IQ Air GC MultiGas (also a good filter for smoke, but louder and with limitations) and by comparison the Pro XL is much quieter. Also missing from the IQ Air is the intelligent air sensor, which is a must have in my opinion. It is a comfort to know the unit is sensing the air and adjusting accordingly without wasting filter life. Another review incorrectly states that the sensor is behind the filters and therefore not working. It is true that is where the sensor is located, but the sensor air intake is on the side of the unit and not detecting the filtered air.

When I burn toast I can hear the unit adjusting to clear the air. It's fast and effective. At its highest speed it can be a bit load, but with the sensing unit this is infrequent and only when necessary to ensure clean air. On the middle speed it is quiet and on the lowest speed hardly noticeable.

Overall really great unit. I plan on buying a Pro L with the intelligent sensor to replace the IQ Air in my bedroom next.

Living in California suffering wildfire smoke, we decided to purchase the Pro L. On its highest setting, it does help reduce smoke down to acceptable level when outside is like 250-500. Very terrible. We complained about Beijing air pollution but theirs barely exceeds 150. Imaging at 500, smoke permeates everywhere. My clothes my blanket, towels all are smoky even after smoke subsided. In the extreme case like ours, on its highest setting, it does a good job purifying about 600-700 square ft space. I suppose you need to have one in each room to be more effective. Instead of buying one big expensive unit like Pro XL, two Pro L or several Blue 121 or 211 in each room will be much better off in terms of cost and energy. The 211 and 121 both uses 60 watts while this one uses 271.

One thing puzzles me is that the 605 has higher cadr (clean air delivery rate) than both pro L and pro XL: Clean air delivery rate (CADR) - Pollen

640 cfm

Clean air delivery rate (CADR) - Dust

500 cfm

Clean air delivery rate (CADR) - Smoke

500 cfm

Whereas the XL and L are at 450 and 400 only. The 605 is only 899 and almost 1/3 of the cost of CL and $100 less than L. Why would I buy the Pro XL, Blueair needs to clarify a little here.