I haveÃ‚ been usingÃ‚ the Sweetwater for a few years now, and have used it on several trips, so I have a pretty good idea of how well it works and holds up.
I bought it for my first backpacking trip, since I didn’t want the extra weight of enough water for the entire trip. The entire trail ran along (and through) a river, so finding water to filter was not a problem.
Being overly curious, the first thing I did was take the filter completely apart to see what it consisted of. I was impressed by how well the threads went together, the overall construction quality, and the smooth action of the pump.
Being overly stupid, I did not read the directions very well, and used it the first time with the water exit tube attached. High amounts of carbon + transparent rubber tube = black rubber tube. It STILL has the charcoal stains on the tube. The stains do not affect the operation of the filter or the taste of the water, of course, but they do show everyone that I am incapable of reading directions. The curse of being male, I guess.
The filter is dual action, meaning it will pump water on the up and down strokes. It fills up a Nalgene or hydration bladder in a minute or two, so you are not spending half your trip collecting potable water. The metal prefilter does a very good job of keeping debris out of the filter body and I have never had a clog or found any large particles stuck in the filter.
The taste of the water always amazes me. I imagine it does not do much to mountain streams, but the difference is readily apparent with coastal water. The sulfer smell and taste is almost completely eliminated the first time you run the water through the filter. Any cloudiness or particles in the water are completely eliminated.
I have not had to replace the carbon microfilter yet. I have heard of people using these on an AT trip, and never having to replace anything.
The weight is very low, but is, of course, more than iodine or chlorine dioxide tablets. For me, the extra weight is worth carrying to remove debris and impurities from my water. A military test ranked the Sweetwater as one of the best filters, only failing in the area of viruses (virii?). Throw in some chlorine dioxide if you are in an area where that would be a problem, and you have an excellent way to filter and treat your water.