AM (or Micropur in tablet form) is supposed to kill all three major forms of pathogens: bacteria, viruses, and protozoa (e.g. crypto). HOWEVER, if protozoa is an issue, AM may require somewhere between 15 minutes and 4 HOURS of treatment time -- depending on water temperature! Not a problem for water stored overnight, but realistically how many of us will wait 4 hours (or even 1 or 2 hours) when hiking in the day?
Up to now, I've just scooped water into my Platypus bladder, drop in a Micropur tablet, wait 15 minutes, and then drink. However, next time, I am going to splice a Seychelle in-line filter between my bladder and my bite valve.
Platy --> AM or Micropur treatment --> Seychelle --> bite valve
The chemicals will kill viruses and bacteria, then the Seychelle will filter out sediments, the bigger pathogens (protozoa like crypto, etc.) as well as neutralize the chlorine taste of the water. This may not be bad for just 3-4 ounces and just a little bit more sucking effort.