It works better than I thought it would. A Rab Strata Hoody ended up being my go-to outer piece for cold weather hunting this past month. Using it over a single heavy baselayer worked well for hiking and glassing around 0. A heavier coat is needed for extended glassing.
The Alpha definitely moves moisture faster than stuff like Primaloft and Climashield, but is warmer for the weight than fleece or wool. It needs to be paired with a more breathable shell to work properly, so jackets like the Strata aren't as warm as you might expect in windy conditions. I'm not sure I'll use the Strata much in non-hunting applications, but for cold weather hunting I am impressed.