I am not sure how one could tell that the quality of the ozone coming out can make such a difference from one system to another if they are both cold corona. Isn't ozone is ozone?
I will jump in on this one. Ozone is generally considered O3, but ozone can also form in to higher, more powerful, allotropes up to O25. These allotropes are known as long chain ozone or polyatomic oxygen molecules (POM). POM is only formed by true cold corona devices or ultraviolet units, but not hot corona.