I’ve owned both the 6′ and 6’6″ version of the Kodiak. I’m a pretty restless sleeper and I like being able to move around inside the bag thanks to the extra girth. At 5’9″and 180-190lb, the 6′ was great, but I second-guessed myself having read that it’s a good idea to keep boots, water bottles, electronics, etc in the footbox of a longer bag in winter. Huge mistake. The 6’6″ bag was so much wider at the shoulders and hips that I couldn’t sleep anywhere near as warm as in the 6′ version. Too much dead air space to warm up.
I wound up buying the shorter bag back from the person I sold it to, as it was more than he needed. For me it’s been comfortable down to low single digits wearing thermals. If you’re built like a rugby player, the Kodiak is great. Otherwise consider a slimmer cut bag like the -10F Lynx. Side note: I wouldn’t suggest adding overfill to the Antelope to try to boost its 5F rating because the down has a higher likelihood of being compressed.
Generally I find WM are pretty accurate in their temp ratings – more so than other brands I’ve bought over the years. The Microfibre series bags are more comfortable for me than the Extremelite series, due to the improved breathability of the MF shell.
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