I got to fiddling with the Sawyer Water Filter. Not sure why it took so long but here we go. Do bear in mind that these are just initial impressions. Maybe the thing will fall apart in a month and I will write that it sucks, who knows. (Though they have a million gallon manufacturers guarantee. I do not think anybody has really put that to the test but it is definitely a positive sign.) Anyway here we go.
The Good: Two words; small and affordable. They cost somewhere around $40 and the dimensions of the filter are about 4"x2"x2". Weight is around a half pound. If those numbers do not illicit some interest I am not sure what would.
The Bad: The arrangement where you have to fill a bottle with questionable water and then filter it by squeezing it through the filter requires some getting used to. It isn't really bad, just different. The need for bladders are definitely the weak link in the system. That being said water filters are a fairly fragile item anyway. They have lots of little pieces like hoses and gaskets. The setup comes with little bladders to use. They seem fine but I would probably look at other options for serious use. Available bladders like those made by platypus might be a good option. I really like that the threads on the filter are compatible with 1 and 2 liter soda bottles which are readily available and almost indestructible. This is how I will probably use the Sawyer Water Filter.
You do really need to squeeze the bottle or bladder for it to work. Not a big deal as pumping the little handle on most filters 1,000 times to get a liter of water is probably more of a hassle. It is however a consideration. Filters like this are not what you would want to use to provide clean water for a family of 5 when the power is out or for a base camp kind of situation. While you could do it that would suck. I think you really want a small compact filter for hiking or mobile emergency use and a larger gravity flow filter like a Berkey water filter for a cabin/ base camp or a bug in type situation.
The Ugly: Please note that this is a filter vs a purifier. The significance is that the system does not eliminate viruses such as Hepatitis or Rotavirus. This may or may not be a concern for you depending on where you live and what you are looking for it to do. Admittedly I am not as educated on the topic as I could be. My semi educated guess is that for areas that have all sorts of nasty diseases like sub Saharan Africa or the 3rd world in general this would be an issue. Also for situations where you might need to make water that could have co mingled with sewage (like a fairly populated area during a hurricane or flood) this could be problematic. I suppose you could boil and filter or something but I am not exactly sure.
My overall (initial) assessment is that these filters are pretty cool and a darn good deal. They would be great for a lot of situations. Given the price of the Sawyer there are a lot of possibilities. For the price of a Katadyn Pocket Water microfilter with a spare element we could get Sawyer water filters for ourselves, our parents and all of our siblings! Storing filters in all manner of kits, having a filter per group member or whatever is realistic given the affordable price point of the Sawyer filter.