This is nice. Everything about the Yukon suggests assiduous, careful hand-crafted to order workmanship. Not a stitch out of place. Each zip runs smoothly. Each press-stud locks firmly into its socket. The Drishell outer feels unexpectedly and gratifyingly durable for a UL fabric. The loft is serious and effective. Everything about the Yukon suggests a step up in standard. It is meant for severe winter weather and no mistakes have been made here. It sits at the top end of my insulation layer range, filling a severe cold lacuna that the Nano Puff and Prism 2.0 do not.
PHD suggest the theatre of operations for the Yukon Pullover is -15C but that some adventure racers use it at much lower temperatures. In the -4C chill of the snow covered Surrey Hills last night, -15C did not seem unrealistic. At 445g (470g in its stuffsack), the Yukon is definitively light for the warmth and protection it provides. By comparison, the Rab Infinity is billed as 510g, although some suggest it is lighter for the smaller sizes and more in keeping with the Yukon. With a box-wall construction (to eliminate 'lines of cold' found in stitched through construction) and filled with exceptional 900 cu.in. fill power down, the Yukon ought to be warm and light. Manufactured with a Drishell exterior and an MX downproof inner, it ought to be protective. Drishell, a superlight windproof and water resistant ripstop nylon, seem tougher to the touch than the satiny Pertex Quantum on the Rab Infinity, for example, and is certainly very water resistant - in fact, as the most water resistant fabric in the PHD range, it is more water resistant that the Ultra which is in MX fabric and which Will Rietveld rated, in his BPL article of 2010 as still significantly water resistant for the weight. The main zip, also YKK, segues into an area of smooth, soft beardguard around the chin which is agreeably snug and comfortable, and runs all the way round the insulated collar.
The zips, high-quality YKK examples, have long cords with thick grips for gloved hands. The pockets are in fact a single pocket going all the way through across the stomach area with an area of down insulation on top of them. I am not as impressed by the MX inner being the only thing between your hands and your body - some insulation there would have been welcome. The fit, despite the enormous loft of the pullover, is snug. Like James Boulter, I opted for a large, after speaking to PHD direct - and very helpful they were too. For your assistance, I am a 39-40" chest, 21" arms, 33-34" waist and 20-21" torso. PHD suggested a large to ensure the pullover did not ride up when bending down and moving around in camp which makes very good practical sense. It is a nice length - unlike the Rab Infinity which I found to be too short on my back - the Yukon, instead, comes down a few inches further. I prefer this, but that is my personal choice.
The hood, attached by a series of press-studs, is also insulated and has an elasticated rim. It feels snug but not over-tight and very comfortable. The fact the hood is removable, rather than part of the jacket/pullover, as with the Rab Infinity, does not affect its performance - no wind sneaks in, uninvited. It does, however, increase the pullover's versatility. There may be few occasions when, if anticipating weather which caused the selection of the Yukon, you'd be using it without the hood, but at least there is the option. I like versatility. The cuffs are the same elasticated rim as the hood and, again, comfortable. They are not adjustable in any way, but I like that - why waste weight on a pointless feature? In an environment where the Yukon would be required, you'll want your cuffs tight against your wrists - adjustability is a pointless feature. I would prefer them to be a little tighter, in fact, and I'll contact PHD about that.
The hem is drawcord-adjustable through two cord-locks either side at the hips. They are easy to operate with a gloved hand and smooth-running. It comes with its own stuffsack which, although PHD suggest it does not pack down very tight, I found to be tight enough and the Yukon does in fact pack down quite small. Nevertheless, I will probably ditch the stuff sack and put it in one of my 13 litre drybags along with other stuff I'll need around camp. Down should be protected at all costs in severely cold weather.