User Review: MSR HyperFlow Microfilter
I owned this product for a summer, and don't think I can recommend it.
As others have mentioned, in the beginning, and under ideal conditions, this thing works great. It's lightweight, it pumps fast, and the floating water-sucker-thing generally stays in place.
The problem, as everyone else has mentioned: It clogs up real fast, and can be difficult to clean.
I took it out with a large group doing a three-week trip. There were about 8 people and about 4 filters, including this one. It slowed down drastically -- to the point where even a single pump was a chore -- within probably 3 or 4 days.
Backflushing, to the extent I was able to do it, was generally unsuccessful at substantially improving its performance. I won't rule out the possibility that I'm too stupid to figure out how to backflush successfully, but I did follow the directions and we had a number of people puzzling over it.
After about 10 days out, I happened across a ranger who took a look at it and was similarly unable to figure out a way to clean it more effectively. A few days later I gave up entirely on using it.
We were using clear, flowing water, generally from streams very close to snowpack, so I wouldn't think that bad water conditions had much to do with it.
I should point out that all the filters we had ended up failing in some way before the trip was over. Sometimes pump handles snapped off, sometimes they just became impossible to clean effectively. We spent most of the last week of the trip drinking unfiltered water when close to the snowpack and using tablets when further away.
Perhaps someone with more patience and better backflushing competence would find this a lovely product, but the hassle isn't worth it from my perspective. I've since purchased an ultraviolet purifier and find that it matches my needs much more closely than any filter I've owned.