I too am considering purchasing the Steripen. It would save me about 10 ounces compared with my Sweetwater filter, which I love, but am looking to save weight and space. I’m still researching Steripen and appreciate all the discussion on these forums as I am learning a lot; however, I would like to add what I know at this point as well. The way I see it, advantages would be less weight, less bulk, quick, and does not affect taste. Plus ultra-violet is a legitimate purification method. Disadvantages is that it’s not field maintainable, but you can always boil in a pinch until you can replace. Doesn’t work as reliably in cloudy water, but they do have a pre-filter, and treat longer if water is cloudy. Biggest disadvantage is that it does not leave a residual that keeps on working (like chemicals). Someone mentioned that if you get untreated water on the rim, you could do like chemical users do, loosen the rim and shake–but think about this. Without a residual that keeps on treating, this approach would only serve to re-contaminate the water you just treated with the Steripen. So cross-contamination with contaminated water on rim, etc. is something about which you still have to be careful. Personally, though, I’m thinking about trying it. Advantages seem to outweigh the disadvantages of it. Although I’m still researching it, my confidence is growing, and I’m seeing mostly good reports from hikers who’ve used it. Thanks for the exchange of information.
Chipmunk Whisperer