I have not been able to find an acceptable travel pillow. Please recommend your best experience.
For your head or back?
I would suggest first checking the hundreds of posts here that discuss travel pillows. Here's a link you can use to start. Then look through those and see if any are appealing. I've given up on them myself - I can't sleep with or without one.
My favourite is this one. It is sort of a coil. So, it can be a double layer under my chin, or I can fold it in half and lay the side of my head on it, and I'm sure there are other ways to use it, too.
For my back, I just use one of my packing cells that is not packed to the maximum. If it's too thick I just take out an item of clothing.
My puffer vest also makes a good neck pillow.
for neck pillow, We love Cabeau Evolution S3 ($40). The foam is soft but it will actually hold your head up. It closes in the front so your head is prevented from flopping forward! Lots of Youtube videos showing it