I have the Steripen adventure and have had no problems with it. The only complaint with mine is that if you leave batteries in it when not using it, it will drain them. I use it and pull the batteries out, I have 4- 5 watt solar chargers (20 watts) to recharge the batteries (4 sets) if needed. They are working on a LED version but it's a long ways out, the Marine Corp is working with them to develop a field unit. UV has been around for a while and is used commercially and also is used through Nasa, the only thing the pen does is allow you to use the same benefits in a smaller package. Steripen has been around for a little bit of time and the earlier models had problems (lamp breakage) but since then they've come along way. I boil my water as a backup if the pen dies but I haven't had to do that yet and you can drink the water immediately unlike the Miox and you don't have to carry around salt or strips like the Miox.
When we also fill our 5 gallon jugs at Wallyworld at 50 cents a gallon, it uses a Culligan system with a UV filter at the final stage as well, we have backups for all our water needs since we have our hurricanes which includes Carbon filters for pesticides, UV for viruses, desalination for salt water and a portable back up distiller. We figure we can hold out for awhile as long as we have water and shelter, then we start hunting for food if it gets really bad.