Toasty! Instant warmth when putting them on.
Tested 'em out this weekend snow camping in the sierras at around 9000'. A storm was coming in. We experienced winds up to 50mph and temps down to 15 degrees Fahrenheit during the late evenings. I wore these along with the Fission LT (new model is now referred to as the Kappa SV). Both these pants and the jacket have windstopper outer material and 200 g/m2 primaloft sport material. Underneath each outer layer I was wearing smartwool midweight base layers and nothing else. I was a comfortable toasty just sitting around camp. I wore them the next morning as well and began to overheat around 35 degrees. In addition to the warmth, the wind protection was amazing. Having 30 - 50 mph winds, was kinda fun minus the snow that pounded you as well. Anyway, the point being the windstopper material is a marvel. In addition to blocking out wind, it helps retain the heat in the jacket as well. The wind just made you loose your balance from time to time, but just felt like pressure against your body. No penetration through the material was perceived.

Before I bought these I a little concerned about the fact that they weren't Gore-Tex. I talked with an Arc'teryx tech rep and he informed me the material was very durable and one step away from waterproof. He assured me the only time the material might let water through was during a heavy, heavy rainstorm. The good news, 1) you'll need these in sub freezing conditions and thus you'll have snow instead of rain. 2) if you do happen to need them during the rain and the material gets wet, the primaloft will still insulate. Primaloft was originally developed for the army as a down alternative for just this purpose. The rep told me I could consider the material waterproof in lighter rain and any type of snow, even wet, sierra snow. I further asked him about sitting in the snow my body heat melting the snow to water. Apparently there is nothing to be worried about. After this weekend, I don't have anything to change my thoughts about the above information.

The full length zippers and adjustable draws at the waist and ankles were great. There is an insulation flap behind the zips so you don't experience any cold spots. The crotch zipper proved to have its own virtue as well. Having full length zips is a great thing to have when you want to get that layer on quick without having to take off your boots.
So why 4 stars. One of the leg zips have the tendency to unzip (an inch or so) when you punch through the snow. I might just have the elastic cinches adjusted a little too tight at the ankles. Hopefully arc'teryx will eventually add a snap closure at the ankle, similar to their waterproof shells. Not a big deal. This problem never caused my baselayer to get wet.

Anyway, have a good time and stay warm. You'll be hanging out at camp feeling like your wearing a toasty pair of sweat pants back home on your couch by a fire in the fireplace.

Have used the tent for a five night backpacking trip so far in the high sierras. Upon rolling in to camp on night one, the skies began to cry and continued on for about an hour. I was forced to set the tent up in heavy rain. The set up worked great being that you set the tent up from the interior. Quick set up, about 5 minutes, including the vestibule. Setup will probably get quicker seeing as I had only done it once before. Minimal water got into the tent during setup, but I was being careful. After the rain stopped there were large puddles on the ground for about an hour. Because I used the ground cloth the water had gotten trapped between the tent bottom and the ground cloth. It stayed there for the remainder of the night. (Note: in my opinion the (accessory) fitted ground cloth is a little big being as it lets water puddle but is definitely necessary to help against punctures. You'll know what I'm talking about when you receive your tent. The silnylon floor is thin, very thin, but also seems to be durable in nature.) I slept with big puddles of water around my body and under my thermarest. No wetness ever seeped through... I was just blessed with a little extra cushion for the evening. The morning came, still puddles but no water had migrated through. The bottom is truly waterproof. Not a single drop of water or condensation came in through the walls of tent either. This was more reassuring after stepping outside to see the ground covered with due. This tent has great storm-proofness but is loud in the rain because it sets up so taught. The taughtness is a good thing though because this tent is very sturdy.

Cons: The tent is a tad on the tight side for two but then again Black Diamond was trying to shave weight, right? A great way to fix this problem is sleep head to toe. Then the tent becomes roomy.
Another semi con is the screen and door have two independent zippers. Adds a little weight. But its only kind of a con because if you only want to use one, the other can be rolled up at all times with the tie loops which are integrated at the bottom of the tent / zipper runs.

Note: When you get your tent, be sure to seem seal before using for the first time. You'll be sorry if you don't. Dust dirt, etc. will get everywhere and your seem sealer wont last as long. The best method I found for applying the seem sealer was to use the included syringe and then smooth over with your finger. Allow for several hours of time and a couple rolls of paper towels.

Tip: A lot of people have complained about the static of the fabric. I got concerned myself before buying this cause I didn't want a ton of dust sticking to the tent. I called Backcountry and the rep. recommended to rub dryer sheets over the interior / exterior surfaces of the tent. This worked like a charm. NO MORE STATIC. Try to use non scented or minimally scented sheets so the bears won't think your tent is candy. Another option to de-static the tent would be to buy the static spray. I'm sure that would also work great if not better.

Finally, the tent has three different stuff sacks, assuming you buy the vestibule. 1) Tent (ample space for the ground cloth as well) 2) poles and stakes 3) Vestibule. This is great for distributing your weight evenly over your pack.

All in all. Great tent, I'm very happy with it. It's pricey, but well worth it. When taking down be sure to leave zippers partially open to let the trapped air out.

I look forward to trying it this winter. My buddy has the ahwahnee which is 2" bigger in every dimension and is a 4 season tent, but it has the same exact floor plan and pole setup as the lighthouse. So I'll try this tent when I'm with him just in case I have to jump over into his tent. I gotta say, this tent is about a third the weight and way more compact in the stuff sack, about 3x more compact. In my opinion the only time the ahwahnee can be justified is in temps below 20F in the snow. Otherwise, its an overkill, go with the lighthouse.