Air Purifiers

I am thinking about buying the oust air purifier, but not sure if it really works. Have you tried it?
This is the one I am talking about: http://www.amazon.com/dp/B000TGC3XM/ref=nosim/?tag=yahoo-hpc06-20&creative=380333&creativeASIN=B000TGC3XM&linkCode=asn

Some details:

I’m a chronic allergy sufferer, in my 20s, and I finally went on Amazon and bought one of Honeywell’s affordable HEPA air filters. It comes with an "Ionizer" feature, which I didn’t know too much about, so I went on Yahoo! answers and the web to research.

Now I know that it ionizes air particles so they a) drop to the ground and/or b) become easier for the air filter to pick up. Seems like a good feature to me. Although, some internet sources suggested that ionizers could be useless and/or potentially harmful.

Either way, if I now want to use my "Ionizer" feature, should I be leaving it on all the time? I already leave the HEPA on all the time, set on the lowest setting (anything louder would be unbearable when I sleep, but the lowest setting is just about right).

Thanks for any information.

-James P.