Rating: 2 / 5
My big complaint with the Steripen Adventurer is that I could not work the switch! It's fine for those with big strong hands (the kind who regularly open jars for their SO), but not for me (I can open most jars, but not all). I would attempt to turn on the Steripen switch until my fingers were sore. Sometimes it worked, but often it didn't. I've heard quite a few complaints from other women about the switch. It's good that it's stiff enough not to turn on while in the pack, but not when it's so stiff you can't turn it on deliberately!
My second complaint is that it is really slow, especially when you're trying to purify water for several people. My filter of choice is a ULA Amigo Pro--I can fill up the container and let it filter on its own in camp. With the Steripen, I was sitting there on the buggy creek bank stirring for what seemed like hours to get enough water for four of us. After a day of this nonsense, I put the Steripen away and hauled out the Katadyn Micropur tablets I carry for backup. I hate using chemicals (especially after a really bad experience with iodine), but anything was better than all that stirring! The Steripen is not suitable for other than solo trips, unless everyone in the group has his own and purifies his own water.
The third problem is the already mentioned issue of requiring a Nalgene bottle, which negates any weight savings with the Steripen. The 3.6 ounces mentioned does not include the batteries, and I wouldn't take it out for a week's trip without fresh batteries in it plus two sets of extra batteries. Steripen Adventurer plus three sets of batteries plus Nalgene bottle total 11.0 ounces. My ULA Amigo Pro filter, plus added stuffsack and a Platypus filter connecter, weighs 8.7 ounces.
The fourth problem is that the Steripen doesn't zap the water left on the rim and threads of your Nalgene bottle after you dip the bottle into the water source. Not a big deal for healthy adults, but a definite concern with my young grandchildren in the party.
The Steripen Adventurer went back to REI right after its maiden trip! I was tempted to give it a 1 rating, except that guys with big muscular hands (like my son, who had to turn it on and off for me) won't have problems with the switch. This gizmo was definitely not designed for females!