New duvet silk or wool (or stick with down)?

[HasaDigaEebowai]

As the title says really.

DS2 needs a new duvet since his is very old and all the feathers have moved to the edges and clumped. I've literally had it for about 25 years and so its served its time.

The plan is that DS2 will have our existing goose down duvet and we will get a new one. I've read over the years about wool duvets and silk duvets and Im tempted but they're expensive.

Which is better, wool, silk or down?

Another vote for wool! I have a summer weight wool duvet and put a blanket over it in winter. I never get hot like I do, under a normal duvet. In fact, wool pillows are next, to help with allergies...

Prefer my wool to my silk one and it's much less cruel.