Which material is best for a shower liner - PVC or polyester?

In my showers I have "hotel style" quick dry polyester liners. I live in a really dry climate and have the window open in the shower and don't close the door, so they dry quickly and don't mildew. If you live in a normal or high humidity area, PVC will mildew or mold quicker if there is not enough air flow. All boils down to proper ventilation and environment. If it does mold or mildew, either style, just pop in the wash with some white vinegar, vinegar kills the mold spores, bleach does not.

PVC would be the better choice. It will repel water better and can be cleaned of mold (should the need arise) than polyester.

Both are good. Both are plastic. Polyester is softer more like fabric.

I have a hotel style with the snap in polyester liner that snaps in about a 1/4 down and it gets washed with the towels every week. Look these up on eBay. One thing I do to prevent mold and can be done with a plastic liner also, is find a nice sturdy plastic clip with a hook on end and clip it to the bottom, center edge of the curtain. We then hook the curtain to a suction cupped basket in the shower. This allows curtain to dry. I never have a moldy curtain.

Depending on the quality of the water- resistant coating on the polyester liner, sometimes it can crack and begin to disintegrate quickly after being washed and spun in an automatic washer.

Because there is no industry consistency on thickness, for this reason some people prefer inexpensive clear plastic shower curtain liners that can be readily replaced when they get too gunked up with soap residue.