I am debating between this and the Theta AR, which I know has a tougher backing at the cost of more weight. The versatility and light weight of the Alpha LT are hugely appealing, though, and I think I'd be more satisfied with it overall. However, I have have lingering concerns about the jacket's durability: I know the shell is tough, but how tough? How does it deal with abrasion on stuff like rocks and tree branches? I'd hate to drop this much on a coat and then have to baby it while scrambling over boulders. Does the Alpha handle routine abuse pretty well, or would I be better served with the tougher (and heavier) Theta?

I now have both and the Theta AR is bomberproof, much like the SV but not cut exactly the same way. The Alpha LT is very durable though and exceptionally light. Both will equally protect you form the elements with proper insulating layers. I would say unless you ski trees hard, thus scraping them consistently the LT will be perfect for you. It really is an exceptional piece of gear.

I can vouch for the Alpha LT. The difference is in the face fabric, not the backer (both have woven Pro-shell backer) I've been wearing an Alpha LT for a couple years, and it's my favorite shell, ever! It's face fabric is way more durable than you'd expect for such lightweight; I've never babied mine (quite the opposite, in fact) that being said, the Theta AR will hold up just a little bit better against abrasion, but it's definitely bigger when it's in the pack. For ultimate toughness, Alpha SV.

I can't vouch for the Alpha LT, but I have the theta ar and have put it through hell. I have been through thick woods, slid down rock embankments, and scrambled through thorn bushes (not a snag). It has been crammed in my backpack numerous times, stored in the floorboard of my truck, and used in all temperatures and it looks like new. It has been the most durable shell I have ever owned (although I recently got a sidewinder sv and have yet to put it through the paces). You can't go wrong with any arcteryx shell.