
NEMO
Disco 15 Series
Spacious for side sleepers; bulky, temp rating optimistic.

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i’m 5,3” and i have a women’s nemo bag that fits just right
I can vouch for Nemo Equipment bags (I have 3 down ones and one synthetic for different temperature ranges). I can also vouch for Marmot down coats (for in-town use not for winter backpacking or camping) but I have never used a Marmot sleeping bag. My 3-season backpacking bag is a Nemo down 15F version that is probably 10 years old now and it is great except for in extreme heat and extreme cold at night. I have an old Eddie Bauer Flying Squirrel Sleeping Bag (modified with velcro) that I use for extreme heat and other Nemo down sleeping bags for winter backpacking. Nemo has a lifetime warranty on their equipment.
Just got back from Algonquin where the temps dropped to 3 degrees C. I was comfy in my fairly new -9 degree C Nemo down bag wearing long base layers only, but I felt if it got below freezing I would need some additional layers. Other commenters are giving good advice when they say a good sleeping pad makes a big difference, especially if the ground is already cold (not just air temps dropping at night). Don't trust temp ratings of cheap bags and aim for something with a rating 15 degrees below the coldest you could expect it to possibly get.
I’ve used an EE 30° quilt below freezing with a Tensor Extreme and been fine. I’ve used a 15° Nemo Bag with a tensor elite above freezing and been cold. I am a believer in the sleeping pad makes the biggest difference solely based on my own personal experience.
I like the Nemo sleeping bags that have the gills. You can open them when it's warmer and zip them up as the temperature drops. Works much better for me than just opening the side zipper, which I find let's too much heat out.
The older I get the thicker the sleeping pad... Where I live, I need 3 distinct sleeping bags - warm weather (Big Agnes), shoulder seasons/early winter (Nemo), and extreme winter (Big Agnes - takes up the whole backpack!) I have an REI half dome tent - big enough for weekend camping, small enough that I could backpack with it if I'm not using a hammock. I also have several Coleman Sun Domes as lenders, and my boys each have a Kelty when they don't hammock. For front country camping, a nice comfy camp chair is worth its weight... consider a lightweight backpacking chair as an addition or alternative. You can enjoy a lightweight camping chair in camp, but hard to take an XXL rocking camp chair backpacking... Consider hammocking, too, but that's a whole additional rabbit hole to travel down.

NEMO
Disco 15 Series
Spacious for side sleepers; bulky, temp rating optimistic.
Hammock Gear
Classic Burrow 20°F
Budget king; very warm but heavier than ultralight.

NEMO
Disco 30
Spoon shape for side sleepers; prone to zipper issues.

Western Mountaineering
VersaLite
Durable, very warm; premium price, too hot in summer.

Katabatic Gear
Alsek 22°F Quilt
Versatile 3-season quilt; secure pad attachment, high price.

Ranked #1
NEMO - Disco 15 Series

Ranked #1
Kelty - Tru.Comfort Doublewide 20
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Enlightened Equipment - Revelation APEX

Ranked #1
NEMO - Disco 15 Series

Ranked #1
Feathered Friends - Egret UL 20/30

Ranked #1
NEMO - Disco 15 Series