The classic Denali is pretty old-tech at this point, warm but bulky and not compressible. The R4 is HIGH-TECH fleece. High-loft fleece (faux fur) outer face, and Polartec Power Dry thermal grid fleece inner face with a windproof membrane in between. Very, very warm, windproof and wicks really well, and relatively compressible compared to the Denali. You will see lots of people wearing the Denali around town or shoveling snow in it, but you won't see a lot of people pulling it out in the deep winter backcountry, but you might see someone whip out the R4. Likewise, the R4 is a bit much if all you are going to do is whip around the icy corner for coffee.

there's nothing wrong w/ the Denali, but the Lightweight R4 is a much nicer jacket. It's got a full windproof membrane that stretches and moves with you, while the Denali just was wind resistant panels on the exterior. the reviews speak for themselves below as to how much myself and everyone loves this jacket.Not sure how it compares to the Denali, but the R4 (topped with a hard shell) kept me warm today with wind chill numbers as low as -20F.R4 kills the Denali...it is far warmer and wind resistant!! The Polartec material is so warm given its weight to warmth ratio, if there is such a thing, I cant believe how light and soft it is...range of motion is excellent and very comfortable. This is a very nice jacket but is a little to girlie for me (totally kills it for me)...too soft and fluffy...if it wasnt it would be easily one I would wear!!!I have worn both in active situations and the biggest difference for me is bulk. The Denali is impossible to pack and hard to layer. Not to mention the fact that the R4 is completely windproof. In short, the denali does not even compare.Added by nwbackpacker: I have both. I use my NF Denali for keeping warm in the house when it's cold out and I don't want to burn as much fossil fuel. I use the R4 for going outside and doing actual activity in. The Denali is stupidly bulky and not windproof, so it's as as bulky as the bulkiest outer layer but not at all appropriate for that task, and as a mid-layer it's way too bulky. The R4 has room to layer, but not quite as much as the Denali, but still *plenty* and it's windproof so you'll actually be able to wear it out in the snow and wind without catching a cold.