I’m on the buckwheat train. Tried different pillows and ended up with buckwheat. The pillow allows you to mold the shape to an extent which makes it extremely flexible. They also come in different sizes and good pillow sellers will either overstuff them or give you a bag with extra stuffing. You can open the pillow up (via zipper usually) to remove and add more buckwheat for even more customization. It’s just extremely flexible overall.