Kayu 15 Men's Down Sleeping Bag

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.

Nemo down 15F is my favorite. I felt warm sleeping when outside was below 30F. Wait for the next sale in REI you can snag it for nice discount.

I love my down 15* Nemo bag. It's a huge warmth difference compared to my synthetic 25* Nemo.

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.