Hi Paul,
I bought my wife a TNF Plasma Thermal and it suits her needs very well but here are a few things you should be aware of in comparing it to a Rab Belay Jacket. We bought it for a very reasonable price in the Bicester Village TNF Outlet - I think they are around the £100 mark at present. If you live nearby, try phoning to see if they have any in stock.
The PL insulation in the Plasma Thermal is relatively thin – I am guessing they used a 60g/m2 PL One - perhaps adding a bit more insulation than a 100 weight fleece. I expect the Rab Belay Jacket to be much warmer as it uses 130g/m2 PL Sport in the body and 100g/m2 in the sleeves & hood. The Rab is a true belay jacket in the sense that you are unlikely to want to wear it except for stops as it is very warm – the Plasma Thermal would be more suitable for all-day wear in cold UK weather. Or indeed the Rab Photon Hoody…
The Plasma Thermal is a genuine waterproof jacket using TNF's higher quality proprietary HiVent Alpha. It's not as breathable as a classic belay jacket but will withstand the rain much better. For this reason it is an excellent choice if you run cold or intend to use it mainly in winter, but it won’t be as versatile as having a Belay jacket plus waterproof shell. However, it is certainly lighter and less bulky than carrying both.
The design of the Plasma Thermal is pretty well considered but, at least in the women’s model my wife owns, it steers towards styling over mountain function in some respects. The zips on the pockets are the kind that conceal themselves once closed which gives it a tidy look but they don’t seem the most robust option. However the hood is surprisingly good for a US jacket and offers respectable face protection. As such it would work as well for skiing as for winter walking. Looking at the men’s model on the net, it seems that it is a little more functional for mountain use and it certainly isn’t one of TNF’s fashion-only items.
Overall, I think the Plasma Thermal is a very nice all-round winter jacket that provides adequate insulation for most uses. If you get one, make sure it is big enough to be beefed up with a fleece or even PL gilet such as the Berghaus Infinity Light Gilet reviewed
here. It would be too warm and not sufficiently breathable for high-pulse activities in the winter, but if you wish to carry only one ‘throw-over’ jacket on a winter walk to cope with cold conditions, rain/sleet/snow and for rest stops I think it would be a very good option. It all depends what you own already (with regards waterproofing and insulation) and what your intended usage will be…?
