Pre or post process water purification?
IMO there is no ideal way to purify water especially in a wilderness situation or when traveling long distances by foot. But despite all the bad press the CDC received in the past year they do have some good and helpful guidelines on it. Sawyer mini and regular are far from perfect but if use within the recommended specifications they are economical and compact. Better to boil and add a recommended chemical agent when possible depending on your water source.
While traveling in remote parts of the USA I have contracted "crypto" and survived with some pain but I was OK after a few hours and the correct medication. (river water while diving, foolish me.) While overseas from a contaminated well I got infectious Hepatitis type A, that took months to recover from and my liver was damaged for years. I also got Giardiasis (Beaver Fever), tapeworms and several other parasites that were not fun to get rid of and caused a lot of discomfort but I survived.
So bottom line: It is best to use the best means possible to purify your water, but no need to obsess about it, you can alway post process your digestive system if your water purification system fails. Hopefully you will not have many days of walking to reach civilization, because that could require additional holes in your belt and many smooth stones to wipe with. LOL
A whole new skinny wardrobe once back home.