Slow, reliable, built like a tank
Ill preface this review with my cut and paste statement that I work as a backcountry backpacking guide in Yosemite National Park. Nearly all of the products I take the time to review have seen at least a half a season, if not more, of use... and Im committed to not bothering to write a review until I feel like Ive really gotten to know a product. I never thought Id bother to write reviews, but Ive recently decided that since Ive spent so much time over these last many years reading reviews, and finding a tremendous amount of value in articulate and well-informed opinions, that I wanted to give back to the community. So, with that being said, here we go...
Since we do some filtering of water in the park we split time between two filters - the MSR Miniworks (which is what I personally own) and the Katadyn Vario. Both are great filters, each with its own strengths and weaknesses. Each time I wind up filtering water I find myself cursing each filter in one breath, and then praising it the next... for nearly opposing reasons.
Let me dispense with this now. MSR = built to withstand the apocalypse. All of their stuff is absolutely bombproof. I own many of their items, and all of them withstand use and abuse. The MSR Miniworks is no exception to this rule, and having clean water is not something to take lightly.
The MSR uses a ceramic filter that will last years and years if taken care of properly. There a few downsides to the filter though. Replacements are expensive, though not relatively so, since a single ceramic filter can potentially last you several years or more. Also, they are fragile. Do not go to sleep with a little water in this filter if it is going to get below freezing at night. The freezing water will swell into ice and crack the filter. Sleep with this filter if you're going to see freezing temperatures.
The filter is field maintainable/cleanable. Pull the ceramic element out, and *very lightly* brush it with a small piece of Scotch Brite, or something similar that has a bit of abrasion to it. Do not scrub the hell out of the filter. It'll reduce its life significantly, and won't get it any cleaner than a light cleaning. The goal is to remove the funk covering its porous surface, not to sandblast it.
The goal, when filtering water with the Miniworks, is to keep the intake tube off the floor of the lake or stream. Try to keep as much sediment and debris out of the intake element as possible. That stuff will clog up the ceramic filter quite quickly, necessitating another time-consuming session with the Scotch Brite. If you can keep cleanish water entering the intake tube the ceramic filter will provide several days worth of clean water without needing any cleaning.
I have seen this filter throw us some curveballs in the field... namely, I've seen the older models (these models use green plastic instead of red for the outer casing) get the small floating ball that creates a one-way valve at the top of the filter out of whack. We've had to disassemble the filter, flush it out, and boil the ceramic element, etc. Within 30 minutes its as good as new. I have yet to see one of the newer, red models have this particular issue.
The downside to the Miniworks is that its a single action pump. Its a slow filter compared to many on the market, for example the Katadyn Vario, with which I am also quite familiar. The trade off seems to be reliability and field maintenance. The Katadyn is FAST. I'm always cursing the Miniworks for being slow. Then I use the Katadyn and I'm cursing it for coming apart.
Once you're home, take the filter out and let it dry, and take the time to clean the filter body. 30 minutes of maintenance will keep this filter and element lasting a long, long time. With proper care this filter is, dollar for dollar, the most affordable and reliable filter around.
If you would rather have a slow, reliable, field-maintainable filter then the MSR Miniworks is for you.