What are the main differences between the Arcteryx Hercules Hoody and the Gamma SV Hoody. Trying to decide which one to purchase. Thanks. Scot

The Hercules is also high loft interior fleece throughout, while the SV uses high loft for the shoulders and back and low loft fleece for arms and sides. Basically, optimized fleece usage in the SV, made to move. The O2 in the Hercules is a warmer thermal layer in midlayer mode. If you want warmth but don't need as much weather protection or you are doing something more aerobic, the Hercules is your jacket. If you need the best weather protection and most durable face fabric, the SV is for you.

BeeCee, you are a smart fellow. On top of that, I wanted to emphasize that the hercules O2 fabric is significantly more breathable than regular Powerstretch. So it's not as windproof, but makes for a better midlayer.

Gamma SV has higher wind resistance and a bit more stretch in the face fabric, and has a fuller cut. Hercules is great as a medium protection outerlayer and as an underlayer. Gamma SV would be best as an outerwear piece (and everyday wear)