If you’re expecting wet weather, the synthetic LPP is easily the way to go. My pack took an inadvertent swim in Idaho this year and I was able to wring out my puffy and wear it dry. The LPP will still provide warmth even when wet, down will not. If your hunts are mostly dry, I’d lean towards the SG.
There is no way in hell that the grumman is warmer than the LPP.
I am a huge SG fan, but would not count on that grumman to keep warm below 32 deg, September use, at best.
I've owned both. No longer own either.. The grumman is paper thin, sewn thru construction and barely 5oz of down...hold it up the light, the jacket is covered bare spots in the insulation. For $300+ it's laughable. The LPP is better, but not by a longshot.They are about the same when new. The LPP is 2.5oz Climashield. That’s the same as their 20° sleeping bag, except doubled up. For stationary glassing and being totally comfortable, the LPP is around a 35° jacket. After a couple months of use, the Grumman is warmer than the LPP.
I've owned both. No longer own either.. The grumman is paper thin, sewn thru construction and barely 5oz of down...hold it up the light, the jacket is covered bare spots in the insulation. For $300+ it's laughable. The LPP is better, but not by a longshot.
Neither would be my choice for actually staying warm anytime after the first snowfall.