The Prism remains a great piece of kit. On the Col de la Seigne, at 2516m, I pulled it on when becoming rapidly very cold as the weather turned squally and I was warm within minutes. We then faced nearly a thousand metres of descent down to Refugio Elisabetta and it breathed sufficiently for me to move quickly to escape the weather. As I have said before, I like the athletic cut too which permits me significant range of movement. Often, even on sunnier days, the wind would engender icy frigity at 2500m or more, so I found it a great summit jacket as well as wearing around refuges when sitting outside, enjoying the atmosphere high up in the Alpine passes. It's impossible to stay inside in refuges! Above the Fenêtre d'Arpette, at around 2700m, overlooking the Glacier du Trient, it kept me warm whilst we ate lunch and longed for crampons to tackle the glacier. It's warmer than the Nano-Puff for example, and the fact it is a full-zip jacket makes it easier to pull on in colder weather. The hood is well padded which is really useful and adjustable either when deployed or when used as a neck-buffer. The elasticated cuffs wrap around gloves tightly enough to prevent cold air ingress but not too tightly so I can still, say, check my Vector. I have to say I would not have bought red myself (it comes in other colours), but I am glad Montane sent me the jacket to test.
It is sufficiently packable that, if compressed, it is only marginally larger than the Nano-Puff so I would find that a 13 litre S2S dry bag, along with all my other essential kit, would compress it sufficiently to pack away neatly. The workmanship remains excellent with but one exception - the hood can be rolled away by means of a small piece of velcro-studded pertex which feeds through a loop. The loop snapped on mine which was annoying as that left the hood unsecured. Montane will need to resolve this minor issue on future Prisms. For me, Mrs M will have to get the needle and thread out! That said, I love this jacket and, when I know it'll be colder, it'll be worth taking with me as my primary insulating layer. In warmer temperatures, when I think I am less likely to need the warmth, the Nano-Puff will do.