Barry, my experience with Steripen pretty much parallels yours. In my experience, most of the issues with failure to operate stem from pushing the button after the electrodes are immersed. Most other failures are related to using low quality or rechargeable batteries. I have fixed several Sterpen failures in the field by simply telling the owner to push the button and then immerse and stir. A couple of failures were fixed by swapping a brand-X battery with quality lithium cells. But, for long trips or for trips where I expect poor, dirty water, I prefer a pre-filter and/or filter and/or Micropur approach to the Steripen.

I have heard a lot of anecdotal tales of really high failure rates for Steripen units. I have never seen any hard data to back these tales. I suspect that if Steripen was as lousy as some claim, the company would have long since folded. Sure, there are some legitimate failures but IMO, most operational problems result from not reading the instructions. I know that this caused all the problems I had with Steripens.

It never ceases to amaze me that people will take untested equipment such as tents, stoves, GPS units and, yes, Steripens into the field; have them fail due to ignorance and then come back and complain about the gear while forgetting their contribution to the mess.