Arc Alpinist quilt vs Alpinist bag

I have to agree with Jonathan here. The "passive" collar on my Megalite is a joke. It is just an overstuffed muff around the bottom of the hood opening. Compared to the MH Phantom 15 I just sold there is just nothing there. In the Phantom, there is a piece on the bottom of the bag and on the top that sticks out 3" and is 1.5" thick with a little cutout for your neck. The pieces velcro together AND cinch with a cord- very effective. I think it is very deceiving of WM to even suggest that there is anything resembling a draft collar on the Megalite. I do think it affects the effective temp range of the bag. In hindsight, I would not get a bag rated for 30* or lower without a true draft collar.

Not fair to compare the draft collar of a 15 degree bag to a 30 degree bag. Sorry. Even my wife's UltraLite 20 degree bag has a much more substantial draft collar. But, between the complete lack of one on a SummerLite and what is provided on a MegaLite, it's not like it doesn't exist.

between the complete lack of one on a SummerLite and what is provided on a MegaLite, it's not like it doesn't exist

I disagree. When I use my bag it is like the "collar" doesn't exist. It does nothing to stop air from coming in when I move around. Just saying.

Wow. I got a Megalight a while back, and I didn't even realize it had a draft collar. And I've slept in it.

A medium (6 ft) nunatak alpinist (sleeping bag, not quilt) has 11.5 ounces of high quality down fill and is billed as a 20 degree F bag.

The WM Ultralite has 16 ounces of down fill and is rated to 20 degrees F.

Not that I've ever used either bag, but the Alpinist has a much smaller head box and it's more dramatic hood means it probably doesn't have/need the draft collar like the ultralite. The sipper looks shorter has well which means less zipper baffle. I don't really think those make up for the 4.5 oz of less down but probably some of it, as well the more enclosed hood might make up the difference in prevented heat loss to make up for how much remaining fill is unaccounted for.

Which is to say, different bag design makes fill comparisons sketchy.

Guilty as charged!

I sleep cold. My overfilled Summerlite has taken me comfortably to mid/high 20s (26-28*F). It is admittedly also a 5'6" bag, so the down'll be a little more densely distributed than, say, in a 6'6" bag. Any lower than the temps I mentioned, I defintely find a good draft collar just about essential. And a warmer bag in general.