How does this compare to the Arc'teryx Hercules hoody? I realize the Herc has a hi-loft interior, so should I expect it to be warmer than an MX? Does the MX compare to bc's Welder?

Some clarification on the previous reply about the Arc'teryx Hercules hoody vs. Gamma MX. The Hercules does have a DWR, and blocks about 60% of the wind. The Gamma MX is better as an outer layer due to weather resistance, but for mild conditions, the Hercules stands up. Hercules is cut to fit really well under hard shells, as insulation.

The Hercules is meant as a mid-layer insulation piece. It does not have the DWR treatment that softshell like the Gamma MX has, so will not be as wind/weather/water resistant. It's meant to be under a shell, so breathes really well and will work better as a layering piece under a shell than a softshell would. When you layer a softshell underneath a hardshell neither breath properly as they're both meant as outer pieces. But a piece like the Hercules underneath a hardshell will provide great warmth while being much more breathable when you're exerting. I have a Hercules (and the lighter weight Griffon) that I use heavily for backcountry touring. They're great pieces for that because of how breathable they are making them great at dumping heat on the ascents. Because of their hard faced outer they shed snow and precip better than a traditional fleece or midlayer if you do drop your shell. They don't cut the wind very well though (you can blow right through them), so when it gets cold the shell comes back on. They make a much better part of a shell-based system than a softshell though.