carbon scrubber are better because they clean the exhaust air before it leaves the grow area and do not use electricity, where as the ozone generator are place behind the exhaust fan and will not remove most of the odor before leaving the grow area
I haven't tried ozone generators are cool but the general consensus around here is just to use the carbon. If you use the ozone generators make sure you install them correctly or you could kill all your plants.
Carbon scrubbers can also be effective with the control of heat, but you usually have to put holes in walls or do some kind of partitioning. The fans make noise.
Ozone generators are a good option if you can't be putting holes in walls or ceilings to vent a carbon scrubber. I do believe they are silent. They can not be used to remove heat from the grow room.