We’ve read the reviews across the web for the Marmot Helium Sleeping Bag: 15 Degree Down and summarize the results below:
Universal Ranking
PeakScore: 92 (out of 100)
User Rating: 4.8 stars 
Expert Rating: 4.1 stars 
Number of Ratings Reviewed: 82
Pros & Cons
Reasons to buy:
User Reviews
- Comfortable fit.
- The second zipper allows for convenience, and lets you use the sleeping bag more like a comforter.
- Slightly water-resistant if there is moisture inside the tent or a leak.
- The zippers are high-quality and don’t snag the fabric.
- Well-made and high-quality materials and construction.
- Doesn’t feel restricting when inside.
- The small zipper on the side allows you to put both arms outside for freedom of mobility.
- Packs away easily and conveniently.
- Lightweight and breathable.
- Keeps your extremities and core warm.
- Can be used in a variety of weather conditions.
Expert Reviews
- A warm bag that is suitable for many seasons.
- 800-fill down provides warmth without being too heavy.
- DWR treated down for slight water-resistance.
- The fabric is comprised of Pertex Microlight, which resists abrasions and scratches.
- The curved baffles allow you to move the down to the colder areas.
- Six-baffle hood for warmth and comfort.
- Foot-box is anatomically constructed to promote comfort and warmth.
- Two-way zippers for easy use.
- Lightweight ripstop nylon is durable.
Reasons NOT to buy:
User Reviews
- Not the lightest or warmest option.
- Lack of a right zipper makes it less efficient.
- Might be too roomy or wide for a small person.
Expert Reviews
- Expensive option.
- The wide fit may be too wide for those with narrow shoulders.
- Lack of a neck baffle reduces warmth.
- Slightly heavier when compared to other similar bags.
Summary:
The Marmot Helium Sleeping Bag: 15 Degree Down is a solid option for backpackers and campers looking for a warm and comfortable bag. While some users find the lack of a neck baffle and heavier weight construction to be less-than-ideal, this bag is a still a solid performer.