I’ve been using ozone for about 4 years and agree with most of what I’ve read in the comments. Of starting another reef from scratch, I’d put one on because it really helps get the water crystal clear.
A few pointers:
1. Ideally use a vacuum air pump that sucks air through a dryer and then pushes the dry air through the O3 generator and to the reactor. Dry (dehumidified) air works better. Poseidon makes both units. I bought mine at Aquarium Specialty.
2. Having the O3 generator outside or in a high air flow area is best. You should not be able to smell it and if you do, something is wrong.
3 . You don’t have to send O3 discharge through the skimmer, but you really should (must) run the discharge through activated carbon.
4. I bought my O3 reactor and a couple others from Geo’s Reef. He even customized a reactor for me based on my specs (pretty cool to do that!). Here’s a link: