Guess I should start with the "Pros"- yes, it does work, yes, it is portable, yes it has helped.... now for the "Cons" (taking a deep breath here)....
I became suspicious of the Zeno mini after the batteries ran out exceedingly fast and the cartridge needed to be replaced almost as quickly. So, being a scientifically-minded individual I started actually tracking uses and how often I had to replace the batteries and cartridges. This thing is just too darn expensive to own and operate if it is in fact a money pit as I was starting to think.
Here are my findings-
Batteries: after 10 uses the batteries need to be replaced, again after another 15 uses, and then again 17 uses after that. (uses hereby meaning individual times I pressed the button. The product is designed for three uses in a row and then shuts itself off "for safety"). The product takes two AAA batteries, and I varied the brands which might make a difference in the results. However, if you need to replace it this often, there really is something wrong. Hello- optional power adapter people please....
Tips: The tips have had to be replaced almost 45 uses exactly- which means my friends, I suspect they are on a timer... pretty shady stuff. If they know that these things will stop working in 45 uses, why can't they make it to last 100+?
Replacements are $18- $20 each, so if you are comparing the Zeno mini to the ThermaClear device, even though Thermaclear is $60 more, the tips don't need to be replaced.
Another drawback to the Zeno- sooooo loud. It beeps when you turn it on, it beeps when it is ready for use, it beeps every thirty seconds to let you know it is working and then it beeps when it is done, and then again to let you know it is powering down.... beep beep beep and the beeping can pretty much rival my microwave in decibels.
It does work, and because the principle is that the heat is supposed to break up bacteria, I have also tried it at the onset of a cold sore and the little guy worked like a charm. However, I am certainly walking the fine line of continuing to reorder the cartridges and batteries or scraping it and getting a ThermaClear.