I’m often asked about pillows that provide comfortable neck support during sleep. My response is to inquire as to what position the person sleeps. If it is on your stomach the pillow is irrelevant. Stomach sleeping is stressful on the neck and lower back and should be avoided.
Back sleepers usually do well with the pillow with a built in neck (cervical) roll. This supports the neck in its normal posture.
Most of us sleep on our side. Side sleepers need a pillow that is thick enough that when observed from the side the head, neck and spine are all level. Thin pillow (feather) and the head drops down. Two pillows and the neck is craned upward.
The pillow that I have been using for twenty years comes in five different thicknesses and we can measure the size that best allows for a comfortable, level head and neck. This pillow also has a cervical roll that allows for people to both sleep on their backs and sides with optimal support.