I just bought a Sawyer Mini to add to my aircraft survival kit. Internally, it's the same technology as a lifestraw, but the form factor is a little more convenient in that you can screw it onto a water bottle or the provided squeeze bag rather than drinking directly from the water source. You can also put it inline on a water bladder hose. Unlike the lifestraw, it comes with a large syringe for pressure backwashing the filter element when it starts to get clogged, so it's rated for 100000 litres (or is it gallons?) which is quite a bit more than the lifestraw. They are about the same price - $20 or so, and I think they have the same filter porosity - 0.1 microns.
Correction: The lifestraw pores are larger at 0.2 microns.