I have the hiker pro as well, we used to work in a lab and the same micron in that filter was used in the lab.

Its a little heavy but I have had no probs yet. Some guys I have met while hiking do not filter, even those that have completed an AT thru hike. They have not been sick either, Im not taking that risk unless I have too.

Chlorine leaves a bad taste in my mouth, but the MSR sweet water isnt as bad.

In every walk with nature one receives far more than he seeks.
-John Muir