I've got a 400 and it is brilliant when one is 'living' outdoors, rather than just 'out for the day'. I also learned that, unless you are in full-on winter conditions on the Cairngorm plateau and wearing a shell layer on top, even the 400 can be very warm; however, I do run hot. There are plenty of viable alternatives out there: Varusteleka make a very good Merino wool hoodie that, for me thus far, has not lost its shape in the way that the Woolpower 400 has. The one thing in the 400-weight range that I find really, really useful and which never leaves my pack is the gilet: it keeps your body warm but still affords you a bit of freedom to wave your arms about.