I had read about the Sawyer Mini Water Filter a couple of years ago, but had never seen a demonstration. I love the SteriPen Adventurer (3.8 ounces without the batteries; about 6 oz with) and have used it on many trips. Of course, it uses batteries. Although it is extremely reliable, you may still want to have a backup (pills). The Sawyer, with no batteries, looks like an interesting alternative.
Be light. Be safe. Be one with the pack.