There’s little to split this jacket and the featured Mammut model. Though the weight is slightly less, the down quality is a little higher and I couldn’t differentiate between the two in terms of the warmth offered. Though they’ve both received similar star ratings, I prefer the Mammut – by a whisker only – as the elastication around its cuffs is better, forming a snugger, draught-excluding fit that still allows me to roll the sleeves up for comfort or ventilation. That’s balanced by the fact that the Nitrous’s baffle is a little more efficient when it comes to staying in place. The Nitrous also comes with a lightweight stuff sack though I usually ditch these in favour of a waterproof drybag; years ago I arrived at one campsite to find a down sleeping bag had become drenched in my pack and I’ve never taken such risks with down products since.