Is 650 fill power good for a down comforter?

It is solid mid-range down. It lofts well and insulates better than feather blends, though 700 to 800 fill power down packs the same warmth into less weight.

Is it warm enough for winter?

For most bedrooms, yes. In a very cold room or for a sleeper who runs cold, a higher fill power comforter will hold more warmth.

What is the 80/20 down-to-feather ratio?

Eighty percent of the fill is down clusters and 20% is feathers. More down means more loft and less weight; the feathers add a little structure and body.

Does the cleaning process matter for allergies?

The down is washed to twice government standards with bluesign-approved soaps, which reduces dust and residue. That helps, but it is not a medical guarantee.

How should I care for it?

Shake it out regularly to keep the down evenly distributed. Wash it rarely, and follow the care label, since down needs thorough drying to avoid clumping.