This review is based on my experience in a friend's car and from his opinions of it over the long he has had. At the end I decided not to buy this based on what I experienced for my usage. But, if you are considering buying this I hope this review helps you decide.
In general when you read about plasma cluster and Sharp it's a great concept; it cleans air and does not require the maintenance that HEPA based filters need.
The Good + Looks. The looks of the generator is very tech and not in your face. It doesn't look weird and is something which merges with the car. + Portable. Carry it from one car to another; so you can use it in your car or in a taxi. + Fits in the cup holder of the car, which agains makes it portable + Quiet. It's not very loud, mostly sounds like a hum. However, I did notice a buzzing noise, if you switch off all the background sounds including radio, fans etc. You may or may not notice it, depending on your ears and how you drive. I drive with music almost always. + Ozone free. Ozone is bad for your health and your car. And I am happy that none of the Sharp air purifiers including this use Ozone; they are completely Ozone free.
The Bad - Effectiveness. This is what you are buying this for and it's effective. However, there is a big catch, it requires time to work, so unless you are using it on long drives you will be hard pressed to notice any difference. + Life. The filter is rated for 19000 hours, which is a long time. However, after that time you will need to replace the ion-generator, which costs around Rs.2000. + Requires maintenance. It needs to be cleaned to be effective. + Plasma Cluster and it's side effects. Read about it on web; there is too much pro and con information about ionisers.
My travel in the car is usually very short, mostly under 1 hour and I found that this isn't all that effective during that time. Perhaps, if I was stuck in traffic jams and was spending more time in the car I would make this investment but, as of right now I am passing this. Just, better idea to keep the car dusted, dry-cleaned on a regular basis. However, if you spend lot of time in the car, go on long drives, or have severe dust allergies this could help; how much, depends on all the above factors.
I hope this reviewed helped and if it did please click Yes below; encourages me to write more such reviews :)