I would use one, but only in water that I was pretty sure was safe to drink anyways. There are two different types of straws, one has chemicals the water passes through, the other has a filter. The type with the filter has a pretty coarse filter, and while it does an ok job, the pump filters do a much better job. If you realize you might be drinking beaver piss, you probably want the best filter you can get. If you are just getting the water right out of a spring, and want to be safe instead of sorry, you'd be ok with a straw. If you are downstream from a cattle pasture, you'll want a better filter, and possibly a charcoal filter, or even better, bottled water.
