I tried the Aquamira Frontier Pro last summer. I've read that it's a 2.0 micron filter, so only filters protozoa, not bacteria. And the CDC recommends a 1.0 micron filter for giardia. It's recommended to use chlorine dioxide (MicroPur or Aquamira) tablets with the Frontier Pro to kill the bacteria and viruses. Having the filter for the protozoa just means you don't have to worry about the long contact time for the chemicals to kill them.

My experience is that this filter is SLOW! Instead of the 1 L/minute rate of the ULA Amigo Pro, when the Aquamira Frontier Pro is rigged as a gravity filter the rate is more like 10 minutes per liter. I tried sucking the water with the bite valve, and got mostly air. It took several minutes to get a cup of water through of the filter with the bite valve, and by that time my whole lower face was aching. Fussing with the tablets was also a pain; you have to wait 20-30 minutes before you can even start to filter.

Your mileage may vary, but I think that "Frontier Snail" would be a more appropriate name for this filter! Plus the Aquamira website's not stating the size of the filter makes me doubt quite strongly their advertising claim that it really does filter 99% of the protozoa.

I also need to filter my dog's water on occasion, when the water sources are stagnant and frequented by livestock. In that case it's to prevent leptospirosis. My dog refuses to touch chemically treated water, so I need a filter that will strain out the bacteria.

Completely unrelated, I keep wondering why all these filters use "Pro" in their name?