Interesting reading this old thread - my pencil's still going strong despite it rolling of the seat of my truck one rainy day and landing in a puddle.
Battery life is (sticks finger in air) about 80% of new - still enough for a multiday charge.
Keep hearing rumors of a pencil v2 - given how much I love my v1, I'm certainly game for a v2 (along with the corresponding iPad that it works best with, of course!)