A close look at two sleeping bags buyers cross-shop. They score within a hair of each other, so it comes down to the details below.
| Big Agnes Rabbit Ears 25 | Kelty Cosmic Down 20 | |
|---|---|---|
| GearScore | 81✓ | 81 |
| Comfort rating | 34 °F | 31 °F✓ |
| Weight | 2 lb 1.0 oz✓ | 2 lb 7.0 oz |
| Warmth-to-weight | 3.8 /100g✓ | 3.5 /100g |
| Packed size | 9.4 L✓ | 10.7 L |
| Fill power | 600 FP✓ | 550 FP |
| Price | $200 | $190✓ |
| Fill | Down | Down |
| Style | Bag | Bag |
| Shape | Mummy | Mummy |
Highlighted cells mark the better spec: Rabbit Ears 25 in blue, Cosmic Down 20 in amber. A blank spec is never counted as a win. A lower comfort rating in °F means a warmer bag, so the warmer bag takes that row. GearScore is the overall rating (0 to 100); re-weight it on the full bag comparison. Prices are current MSRP.
Put the Big Agnes Rabbit Ears 25 next to the Kelty Cosmic Down 20 and the trade-offs are clear. They are close enough that this really is about which handful of specs you weight most.
The Rabbit Ears 25 is 6 oz lighter, stronger on warmth-to-weight, and more packable (9.4 L vs 10.7 L). The Cosmic Down 20 is warmer (rated 31°F vs 34°F) and $10 cheaper. Their GearScores land within a couple of points (81 vs 81), so neither runs away with it.
Pick the Rabbit Ears 25 if you care most about low weight and warmth-to-weight, which makes it the better call for counting grams on long miles. Pick the Cosmic Down 20 if warmth and price matter more to you, or you are focused on colder nights and shoulder-season trips.
The Big Agnes Rabbit Ears 25. It is 6 oz lighter than the Cosmic Down 20.
The Kelty Cosmic Down 20. It is warmer (rated 31°F vs 34°F) than the Rabbit Ears 25.
They are nearly tied at 81 and 81 on the default algorithm, so re-weight the score to your own priorities to break the tie.
It depends on your priorities. Go with the Rabbit Ears 25 for low weight, or the Cosmic Down 20 for warmth. The spec table above shows exactly where each wins.