Ozinators have been debated and discussed a few times here
. Doing a search might help you find some info about them.
As far as benifits:
1) They help the water stay clean. However, the debate is "how much cleaner?". I have found that my Freshwater Ozinator works great. I love it and recomend it. Some folks claim that they can't see any noticable difference with an O3 unit.
The Disadvantages:
1) O3 can discolor the underside of your cover
2) It can deterioate pillows
3) Some folks wonder if the price is worth the benifits.
4) In some instances, O3 can iratate people. I've read about cases, but have never spoken or met anyone who had a problem with this.
As I said, I think they work great. I have great luck with mine. However they are only a suplimental part to your overall water care program.