I ran into this surfing the web. This was a little infomercially for a Ted talk, but seems interesting.

Video

Has anyone used one of these? They aren't cheap ( $120 at amazon).

I don't see the point. There are products that allow for greater volumes of water to be purified to a greater degree for the same or less money.

I haven't used one, but a couple of things to note:

They've been around for a while - the TED talk video was July 2009. I don't know how much they have changed the product since then or what other competition has come into being in the meantime.

I don't believe the product was devised with the primary idea being use by hikers.

The product is not just a filter, it's a purifier, so you'd need to compare apples to apples.

I use the Sawyer Water Filter Bottle in the BW and consider that adequate protection, but it is not a purifier.