Depends on your point of veiw here. Ozonizers are quite an effective way to kill mocroorganisms, as well as eating plastic and rubber. I have one that I do not have hooked up yet, an Aquazone 200, it is intended for use with my Berlin Classic skimmer. I figure once I kill everything then the skimmer will collect it.
I am having second thoughts about using it though I don't know if I want my system that sterle. My thought is to make the 55 into a refugium with deep sand with macoalgea.
As far as which one is more benificial. Not having used the ozonizer yet I can't say for sure., but systems with ozonizers run very clean, squeeky clean in fact, crystal clear squeeky clean.
I know that the water that is treated with ozone should be run through GAC, or you run the risk of poisoning the system and killing everything.
Thomas