RAB Mythic G vs Decathlon MT500: What a $525 Down Jacket Actually Buys You

Introduction

Put two hooded down jackets side by side and the spec sheets can look surprisingly similar. Both jackets here use responsibly sourced down, both have hoods, cinches, full zippers, and hand pockets, and on paper both should deliver a comparable amount of warmth. The difference is the price. One sells for $525, the other for $140.

That gap raises an obvious question. Are you paying roughly four times more for a genuinely better jacket, or for details most people will never notice on the trail? The answer sits somewhere in the middle, and it comes down to materials, construction, and the parts of a jacket that never appear on a spec sheet.

What You Get at Each Price Point

Start with the numbers. The RAB Mythic G is the lighter of the two at 277 g, and it gets there with 127 g of 1000 fill power down inside a 7-denier shell fabric. The Decathlon MT500 weighs 440 g and uses 149 g of 850 fill power down in a 20-denier ripstop nylon shell. Both jackets are cut in a size large that leaves just enough room to layer underneath.

The feature lists overlap more than the prices suggest. Each jacket has a hood, cinches, a full zipper, and two hand pockets. The MT500 adds a chest pocket and two internal drop pockets. Both use RDS certified down, which means no live plucking, no force feeding, and a supply chain that is audited.

Fill power is where the two designs diverge. Higher fill power means the down clusters are fluffier, so a smaller weight of down delivers the same loft and warmth, along with better compressibility. The Mythic G pairs that fluffier down with a much lighter shell fabric, and together those two choices explain most of the 163 g weight difference between the jackets.

RAB Mythic G: Ultralight Shell and High Fill Power

The Mythic G is built around weight savings. At 277 g it disappears into a pack, and the 7-denier shell packs down small. Inside, a reflective coating is applied to the lining to bounce body heat back toward the wearer. That coating does appear to add a small amount of warmth in still, dry conditions, though the benefit is best treated as modest rather than transformative.

Construction is the other half of the story. The Mythic G uses sewn-through seams arranged in small squares, which creates more seams across the body than a simple horizontal baffle layout. Every seam is a point where heat can escape, and the very thin shell also lets more wind through than a heavier fabric would. The result is a jacket that performs best in calm, cold, dry weather.

Decathlon MT500: More Features and More Fabric

The MT500 takes the opposite approach: a little more weight in exchange for more fabric and more pockets. Its 20-denier ripstop nylon shell is roughly three times the denier of the Mythic G shell, and that extra material shows up as noticeably better wind resistance. The 850 fill power down is also springier and less delicate than 1000 fill power clusters, so it resists moisture and grime more effectively and recovers its loft faster after being compressed or squashed.

Alongside the two hand pockets, the MT500 includes a chest pocket and two internal drop pockets, which makes it easier to live with day to day. The trade-off is bulk. At 440 g it is noticeably heavier and takes up more room in a pack.

For anyone who is not counting grams, those are easy compromises to accept. The MT500 is the jacket that keeps performing when conditions are less than perfect.

Warmth, Wind, and Moisture: How They Behave Outdoors

On paper, 149 g of 850 fill power down and 127 g of 1000 fill power down should produce roughly the same loft, and therefore roughly the same warmth. In practice the two jackets trade places depending on the weather. The Mythic G comes out slightly ahead in calm, dry, cold conditions, where the reflective lining and the lighter build have the advantage.

Introduce wind or damp air and the picture flips. The heavier MT500 shell blocks more wind, and its lower fill power down handles moisture and dirt better while springing back into shape more quickly. Anyone who spends long days in changeable mountain weather will notice that difference more than they notice the extra grams.

Durability and Construction Notes

Both jackets are well made, and neither has shown a pattern of problems. Down jackets in general are more delicate than hard shells or synthetic insulation, and neither of these is a candidate for bushwhacking or heavy abrasion. That said, the Mythic G is technically the more fragile of the two. Its 7-denier shell offers less resistance to wear, and the 1000 fill power down is more sensitive to moisture and grime, which can mean washing it more often to keep it performing at its best.

The MT500’s heavier fabric and springier down give it a durability edge, and that edge matters most for people who wear the same jacket hard, season after season.

Price, Value, and Where the Extra Money Goes

Not all of the price difference is visible in the fabric. Part of what a premium brand charges for goes into quality control, research and development, human and environmental sustainability programs, and community participation. How much those things are worth is a personal judgment, but they are a genuine component of the cost of a jacket like the Mythic G.

Distribution explains another chunk of the gap. The Mythic G is sold primarily through third-party stores, so the difference between manufacturing cost and retail price has to be wide enough for those stores to make money. The MT500 is sold directly to consumers, which lets Decathlon operate on smaller margins and hold a lower price. One practical upside for the Mythic G is that it frequently appears at 40 to 50 percent off, and at that price the value calculation changes considerably.

Who Should Buy Which

For most people, the MT500 is the better buy. It costs a fraction of the price, carries more pockets, and handles wind and moisture more gracefully. It is the jacket to choose if you want one down jacket that covers everyday cold weather and most outdoor use without much thought.

The Mythic G earns its place for a narrower group: backpackers and outdoor users who count grams, need a jacket that compresses down small, and are willing to accept a thinner shell and more careful care in return. At full price it is a specialist purchase. At a steep discount it becomes a much easier recommendation.

Conclusion

Two down jackets, similar warmth on paper, and a price gap of nearly $400. The Mythic G is lighter, more compressible, and slightly warmer in still, dry cold. The MT500 is more weather resistant, better equipped, and far easier on the budget. Decide which of those priorities matches how you actually use a jacket, and the choice becomes straightforward.