Katadyn Mini

Used it to filter (clear) water from streams in lower mountain reaches. Worked fine for about 20 liters in total (spread over several days), then pumping suddenly became extremely difficult. Field repair (filter cleaning, pump oiling) did not improve performance...I don't have explanation for this.

Bought one in Amsterdam in 2006, as I was expanding my kit in preparation for some extended hiking. It worked fine, until at one point the screw of the top part which is connected to the ceramic filter broke. I couldn't be much further from Amsterdam at the time, I was on Tasmania. To my surprise, I found a shop in Hobart that stocked exactly this filter and I bought a replacement part. Since that happened, I don't press the top part when pumping, and my filter still works fine.

A few months later I was back in Amsterdam. The shop where I had bought the filter reimbursed me for the replacement and said that they had similar complaints. I guess it's a design flaw. Still, good service.

By the way, I never managed to get 0.5 l in a minute. Even with a clean filter and a clean water source, it takes me at least twice that. Not that that really bothers me, usually I have enough time when I'm on vacation :-)

Found one of these on sale, thought I would try it, after all, it is a fair bit smaller and lighter than my old standby, the Katadyn Hiker.
Big mistake! Try to pump anything other than crystal clear water,the filter will clog after 5 or 10 strokes.
Also, the water input tube needs to be detachable to enable separate storage from the pump/exit line to prevent cross-contamination of the 'clean' water stream.
Also, no way that the pump will process 500 ml/minute. I would say half of that, tops.

Not Katadyn's best effort,IMO.