I've used Sawyer Filters for several years filtering backcountry water sources while hiking. I would stay away from the Sawyer mini (the flow-rate on the mini makes me want to punch puppies) and buy the full sized Sawyer filter. Usually, filtering water for two people, I have to backflush it once a week or so. Drawbacks to the Sawyer is the Squeeze bags they come with are prone to leaking and if you aren't using a gravity filter, squeezing the bags to force water through the filter can be come tedious. Strengths are lightweight (not as critical to overlanders, but very critical to hikers) and the .1 micron size filtering. Will still need to boil or treat with UV light to kill viruses.
Most water stored for a long time will grow bacteria of some sort, unless everything is sterilized before hand. Hard to do that when overlanding. Best thing to do is to treat water in small batches and not store it more than a day or two in containers before drinking it. Boiling water for cooking kills the organic organisms, but not the man-made poisons that may contaminate water.
As much as I like the idea of guzzle H2o, I balk at the price tag when a Sawyer filter is ~ 40 at Wal-mart. I'm sure a lot of that cost is in the battery. Maybe make one without the battery?