Yes, I have used both during trips in Ecuador. While each has inherent advantages and disadvantages, I will say I prefer the MIOX.

Why you say? Just my opinion, but the MIOX is sturdier then the Steri-pen (I have the original version, the new one may be better) and has the added advantage of producing a solution that can be used to disinfect surfaces. I know, I know, I promised to run an in-depth qualitative study on using the MIOX solution in concentrated form on surface disinfection and someday I will. For now, I did a quick “experiment” a while ago using a 4X solution and spayed it onto a heavily (bacterial) contaminated surface, culturing the surface at 10 minutes and 20 minutes and achieved a significantly reduced bacterial load (qualitative only). For me this is important, as my trips are for providing medical care in remote areas. I use the solution to decontaminate tabletops, etc. between patients. I know this not an approved use, but in the field it works.

The Steri-pen is good if you someone offers you a glass of water and if you can without insulting your host use the Steri-pen, it provides one the ability to accept water from almost anyone. I have used the Strei-pen, but for me, found it awkward to pull it out in front of my hosts to sterilize the glass of water they just gave me. I actually found it less awkward to kindly refuse their offer, saying that I had my own water (previously treated).

Pete