First, let me start off by saying this is a wonderfully-made, quality shell. I'm 5'6" 150lbs, and after reading many reviews I got a size Small. It fits me perfectly with just a t-shirt underneath. But I'm not sure about the fit once layers are added. Today is in the single-digits where I live, so I thought I would try it out. I wore a tight thermal shirt with my TNF Redpoint jacket under the Theta AR. The Theta is just so close-fitting that there just doesn't seem to be enough "space" between the cold air and my skin, so I could feel the cold coming in a lot...it's as if the tight fit of the Theta is compressing the insulation layer too much and making it less of a barrier. Not to mention, the armpits rise up quite high and press against my underarms...I felt the outside of the jacket armpit, and there was a lot of warmth escaping. I would probably be warmer just wearing the Redpoint by itself. I've tried on the size Medium at the store and it's pretty big on me with layering and HUGE on me without layering. Now if only there was a size that's between small and medium, it would be perfect for me. So I'm going to keep the small and use it for spring/summer/fall, when I'm not wearing an insulation layer underneath. I might try to find a used Medium for the winter, when I need layering and warmth...but these things are not cheap, so it really sucks that I have to do that to get 4-season use out of it.
This frustrates me quite a bit, since lots of people writing reviews who are bigger than I am say the small is a little loose on them. It's definitely bigger than the average small, but not as much as I thought it would be. Does anybody else notice this?

I own lots of winter jackets. What can I say, I have become a jackethead since moving out west. I own 8-10 North Face jackets, a Marmot and a few Columbia's. But if I had to give them all away and keep only 1, this would be it!!

This is the warmest jacket I have ever owned. Period. TNF Plasma Thermal comes close, but I'd have to go with this one. It is VERY lightweight but somehow VERY warm. Wind does not penetrate the material. I keep thinking it must be some kind of magic jacket...I wore this over just a t-shirt outside in 5-degree weather, windy with a windchill of much lower than 0F, and I was warm!

The "snorkel" hood is interesting and at first I didn't like it; it bunches up behind your neck when you zip up the jacket without wearing the hood. BUT, when you DO wear the hood with the jacket zipped up, it might look a little silly but trust me...this thing keeps your whole head nice and toasty (minus the face, of course). Now I just can't do without this hood! Get a good waterproof shell to use when it's raining and you are SET. I'm so blown away by this jacket!!!!

Wish I could give it 6 stars!!

P.S. If someone could find the 2007 version (medium) in blue (like this one: http://www.jacketreviews.com/Reviews/Synthetic-Jackets/The-North-Face-Redpoint-Optimus-Jacket) I would buy it from you!! I wish TNF would bring back some old colors.

This jacket is great! Really light and not bulky-feeling at all. The primaloft insulation (my personal favorite) is very thin for the warmth it gives. I recently wore it in CO during our cold spell when the temps got down to well below zero and it was very nice. I can wear just a t-shirt under it down to about 10 degrees F (probably lower when I'm moving around a lot and creating more of my own heat). I'd say that with just a bit a layering, like a thermal and a very light fleece it can be worn to well-below-zero temperatures. And of course the pitzips help tons when things heat up, which isn't hard to do in this jacket. The outer material feels nice and smooth, repelling pet hairs...I have 3 cats and a dog, and my BLACK plasma thermal never gets "hairy"! Unless you're intent on a 3-in-1 jacket, I would highly recommend this one!