I finally switched to Aquamira - it works very well. I have an MSR miniworks filter that I used about twice before I got into the Chemicals. it is the second one that I have had and if you want to carry 14 ounces for the purpose of filtration it works very well. I think it cost me 79 or 89 (can't remember). The first MSR filter that I had lasted for three years and is still in great working condition - but instead of replacing the filter I just bought a new one - dooh! Then I read up on chemicals and started using them instead.
The thing I liked about the miniworks is that you can completely field maintain it -- very easily. And the filters last a looooong time. Having to replace filters can eat a hole in the old wallet.