Marmot - Wind River -10° Sleeping Bag

Marmot is a solid brand, like the other commentor said its a personal choice. I would invest in the Marmot down fill bag myself and thats based on the longevity and utility of all my other Marmot purchases.

For a lot of backpacking brands, if you buy 2 bags; one with a left zipper and one with a right zipper ; you can simply zip them together (along with using them independently. I have Marmot bags that do this so my wife and I can carry our own gear but sleep together.

I used to use a Sea to Summit Womens Etherlight Xtreme pad. It turns out it's just too cold for me. Even though it has been tested, I believe it's so thick that the air moves around when I toss and turn, churning up cold air. I tried a Neo Air Xlite. It's not comfortable for me, but incredibly warm. I settled on the Nemo Tensor All Season. I also have an Exped pad. While it's warm enough, it's not as comfortable as the Nemo. Make sure your pad is warm enough. If the cold is coming from the ground, it's the pad, not the bag that needs to be changed out. I found that I sleep about 20 degrees colder than most ratings. So, I use an Enlightened Equipment Conundrum 10 Degree for the colder weather. Then go to a 20-degree Enlightened Equipment Revelation. The Conundrum has a 3/4 zip, which allows for the warm air to stay inside the bag. It does not unzip the way, so it won't lay flat. I sleep with a buff on my neck and a fleece hat. I'm warm at 34 degrees, but I also need to use my fleece or puffy. At 25 degrees, I start getting cold. I have also tried a Marmot bag and an REI bag. They weren't warm enough for me. I believe Katabatic and Featheted Friends may use more down, thus making their bags or quilts warmer. They are more expensive than EE. In April and May, I can switch to my Revelation, which does open all the way. I would not use the Conundrum in zero degree weather because I sleep cold. Nor would I ever choose to be out in zero degree weather. I have a 40-degree quilt that I made for summer use. I sleep cold enough that I am uncomfortably chilled in it when it's about 60 degrees at night. Some people will tell you the EE quilts are not warm enough. They used to use less down but have changed it to match the standards that most others use to achieve the loft needed for a designated temperature. You should be able to see the fill weight on each manufacturers website. Pay attention to the width and length of the quilts or bags. It will help you compare apples to apples. Only you will be able to tell what will be warm enough for you. I don't like using a mummy bag, so the quilts work well for me. You could consider using a liner. It may help boost your bag or quilts rating. I think you will get more warmth for the ounce by getting a warmer sleeping pad. You will probably need to practice in your backyard or some safe place to help you determine what works for you. It frequently test my gear in my backyard, so if it fails, I'm steps away from the house. You may also want to consider purchasing from an entity that allows returns, like REI or MEC. I also sleep with warm socks. I tried Alpaca wool, which worked well. However, I found that using two pairs of Alpha Direct fleece socks works just as well. I bought one a size bigger for layering. This allows me to bring two pairs when needed or leave one pair home in warmer months. You have to look at your sleep system as a system, not as individual components. Combing my puffy, fleece, hat, socks, and yes, even gloves, help me adjust to different temperatures.

I second the 2 sleeping bags instead of one, that way you can really bundle yourself up in there. I have a Marmot one and it’s excellent!