opinion on air purifier?

thinking about getting one for a room many people are in. many of us have allergies. it's for a small room (15'x8').  just wondering what your take on them is?  do they work?  i am interested in keeping the room dust and pollen clear (or as much as possible). i looked on consumer reports and they had great reviews for models for larger rooms, but not great reviews for smaller rooms. wondering why that is?  and what is the harm in using a larger one - if it is more effective?

if you happen to like a make/model...please pass along. thanks!

any/all help is most appreciated. thank you!

I used three during a renovation in three different areas of my house- it seemed to really help cut back on dust and smell. I also use them when I first put on my heating and ac first time of the season. I feel like it helps remove stagnant air, but who knows... I saw someone selling one in one of the fb sales groups at half what I paid for I think one of the  same models I have. Not sure if it’s still available, or if it’s one of the well reviewed models, but u may want to check it out. Does Dyson make them yet? I could do with a “cool” upgrade

i have a Rabbit Air and I love it.  It works great and their Customer Service is awesome if you have questions.

After we moved in and had experienced some issues with everyone in the household coughing after some renovations involving skim coating pretty much all of the walls on our ground floor we decided to purchase a basic air filter so that we'd have in case it was needed again.

We ended up with this one which is popular at Amazon: https://www.amazon.com/GermGuardian-AC4825-Sanitizer-Allergens-Guardian/dp/B004VGIGVY/?th=1

It seemed to help, although the skim coating was completed before we actually had it. 

We don't have any medical conditions that would make us really need a purifier, so I can't say for sure how well it works, but we think it was effective. It does end up circulating enough air so that it can be used to replace a small fan, so we use it during the warmer months primarily for that reason.