The "Alchemy" material seems to be of lighter gauge, which to me is a more than equitable trade off for saving three to five ounces. I have now worn mine for two seasons mainly underneath my backpack with excellent results. I've stayed dry & nothing has ripped.

I've had this jacket since it first came out and worn it traveling to other countries multiple times hiking and bouncing around on rocks, on backpacking trips and never had any issue with it. It has held up amazingly well.

I own this jacket and have worn it through torrential downpours in Kentucky and Louisiana, which is the worst rains Ive ever experienced anywhere in the US. It is definitely waterproof! As far as the durability of the material goes, its pretty darn tough. I wore this jacket through alot of brush cutting at my hunting camp this last year. The camp being in Louisiana is full of thick briar patches and lots of sweetgum trees. At first I worried about this jacket but after a couple weeks of riding the quads through the thickets while blazing our hunting trails Ive yet to have a rip, nor even a thread come loose. I bought this shell based on a review it got in the Backpacker 08 gear review guide. I am more than happy to have made the purchase and would make it again at least ten times before trying anything else as it can't be beat for price, weight, packability, durability....and most importantly waterproofability!