After a few years of leaving the mountain with damp layers due to moisture soaking through my jacket, I decided to upgrade to a waterproof shell. Let's just say I couldn't be more pleased. The venting system is great, keeps a good air flow going when you don want to overheat. I expected the GoreTex to not let any moisture through, and it lived up to that, but I was really impressed by the aquazip zippers. They aren't very smooth to slide up and down, but man, they do their job well. I've been out in a couple heinous rainstorms and they're yet to let anything through. And despite being totally waterproof, it is ridiculously light and packs down tiny, so think there's any chance you might need it, you can just stuff it in your pack.
One thing to note, the handwarmer pockets are not actually fleece-lined like the item description says, but it hasn't bothered me at all, considering I have gloves on 90% of the time when I'm wearing it.