I bought this jacket last year after considering a few other models from a few other companies. I think what did it for me was the brand's stellar reputation, the design of the jacket, and the reviews.
Arc'Teryx is a great company, and they're constantly churning out great gear. My other two pieces of 'Teryx gear are the Atom AR and the Fission SV. The Atom is by far my favorite down jacket, and the Fission is the ONLY jacket I have (and need) for -40ËF/C weather. So the point here is, Arc'Teryx knows what they're doing: they make great outdoor gear that lasts.
So what about this jacket? I've used this jacket in everything from a walk in light rain on 60ËF day, to snowboarding on a -20ËF day (+ wind chill). It it perfectly windproof, it breathes very well, and it's perfectly water proof. Moreover, for being an alpinism-grade shell, it's very lightweight.
I'll share one quick story to convince you that this is the right shell for you, no matter your needs. After backpacking for about three days and ~50 miles in Norway's Jotunheimen National Park, I'd finally made it to the base of the mountain I was going to climb (Falketind). It was pouring buckets of rain, and even though the last approach had only been a couple hours of hiking, I'd been walking through it the entire time. I pitched my tarp, I crawled under it, and to my utter amazement, I was BONE dry. Now here's the good part: because it was so windy, I hadn't had much time to make my shelter wind-proof. So, after crawling in my bivy and realizing I was sleeping in a wind-tunnel, I took this jacket and hung it across the entrance. Not only did it keep out the wind (and rain) the entire night, but the next morning when I was packing up camp, it was dry within 15 minutes of wearing it. I don't know about you, but that's the kind of protection I expect. While the price may be high, this jacket still looks brand new after the months of abuse I've put it through.