I am wondering. There doesn't seem to be...
I am wondering. There doesn't seem to be that great of a difference between the Pinnacle and the Lithium other than the type of down fill. According to the temp ratings there seems to be about 4 degrees of separation. Are they very similar in performance or does the Pinnacle do better with warmer temps. Or are they about the same?
Actually, the better comparison to the Pinnacle is the Helium bag, which is also rated to 15F. The Lithium is rated to zero degrees. Biggest difference between the Pinnacle and the Helium is fill power (800 vs 850), weight (2 lb 8 oz vs 2 lbs 2 oz) construction and price. The Pinnacle uses a slightly heavier and more rugged baffle material that will stand up to more abuse and has a more elaborate footbox baffle system, that again, will stand up to more abuse. This adds a bit of weight, but it you plan to use your bag often it will last longer. The Helium is built to be as light as possible and so Marmot opted for a slightly lighter baffle material and a simpler footbox. In a nutshell, the Pinnacle is best for hard users and the Helium is best for ounce counters. Hope that helps.