If I would choose one sleeping bag for the rest of my life, this would be it.
It has the best warmth to weight ratio, which makes it the best three season sleeping bag.

Outdoor gear lab writes:
The MegaLite is a fantastic sleeping bag, especially for backpackers who are trying to strike a balance between a light pack and sleeping comfort. For dedicated backcountry travellers, the performance benefits of this bag are worth the premium price. In our experience, premium down holds up better to being repeatedly compressed than lower-quality down or synthetic insulation. This means that over the full lifetime of a bag, a MegaLite could ultimately be cheaper per use than some lower-priced bags.