I purchased a bilge buster a few years back after trying everything else, so I thought I'd share my experience, apologies in advance for the long post.
The previous owner hadn't been thorough about dealing with small leaks in port lights, windows, etc (all now repaired), and that, in combination with a fuel tank leak (also replaced) made for a mold/diesel/boat smell so powerful, that upon opening the boat after a week away, it would literally take your breath away. Furthermore, after only a few minutes aboard, clothing and skin would absorb this putrid smell and stay on you all day. First line of attack was cleaning from top to bottom as thoroughly as possible in an 80's vintage boat, and replacing soft goods within reason. It definitely helped but the smell was still fairly strong. After much research and going over the already discussed pros and cons, I went ahead and installed the bilge buster. For the most part, it was mounted in the salon and we left a small fan running to circulate throughout the boat. It took the better part of two seasons (we're in the northeast), but the smell is gone. I did notice that some rubber and plastic bits within close proximity (3-4') of the ozone generator deteriorated and I've had to replace a few things. Since the ER wasn't the main source of the smell, I didn't use it much in there and haven't seen any negative effects. Whenever I arrived at the boat after having it running, I would open the door, hold my breath, switch it off, quickly open the salon windows and leave. 30 min later, the smell of ozone was long gone.
Now that the problem is resolved, I don't use the ozone generator anymore. Just meticulous cleaning, leaving ports/windows/hatches open as much as possible and running a small dehumidifier when it's closed up.
Having said all that, if I had to do it again, if I could avoid an ozone generator, I most certainly would. But, the truth of the matter is that on any boat, there are literally thousands of spots that you cannot physically clean short of tearing the entire boat apart down to a bare hull (not realistic), and replacing every cushion, mattress, curtain, etc at the same time (also not realistic). I've heard there are some fogging enzymes out there that work, but haven't tried them (Pureayre). If anyone has any experience with those, I'd love to hear about it.