I used it in a travel with my family, using tap water to refil our water botles. The water allways have the taste of tap water (in Brasil it supose to have chlorine taste) , but not bad at all. Whe didnt notice any sickness or diarrhea at this time.
It is light, but not light enough to be dropped and forgetting at a small backpacker to be used all the time. It is easy to use but you have to take care with the possibility of the water (not filtered) drain from the top of the cup and wet your jacket or pant.
I did a test with bad water, in a small river near my house. I dont have the test of the non filtered water to be used as a control but I can claim that is not potable at all.
The result is good but the filter let drain a great amount of heterotrofic bacterias (result 1600 UFC/ml, the value accepted is less than 500 UFC/ml) . Those bacterias are not healthy, but the device filtered all fecal coliforms and Escherichia Coli Faecal.
I know the purpose of this device is not to be used with polluted water but I think that it could be a good illustration test. Using a very bad water in that test, I could see that the water was filtered and be turned clean, but not completely healthy water, that could be used at situations of emergency.
Now, I take it with me every time that I travel with my family and I save a lot of money, that i usualy use in water botles.